What branch should i join if i want to be an F-35 pilot?

Well, you have options. The Air Force, Navy and Marines use it... So I suppose the question boils down to preference. Do you want to be in the military, or the Air Force?

Well, it's flown by the Air Force, Navy, and Marines. The Air Force is overall probably your best chance, just because they'll have the most. That being said, it's going to be a long, tough road to get in that cockpit. You will have to 1) get a commission, 2) qualify for pilot training, 3) complete pilot training, 4) get a slot flying fighters, and specifically the F-35. I was Army, so don't know the details, but I kind of think of it like flying Apaches in the Army. As an Apache pilot once told me, "There are 2 types of aviators in the Army: those who fly Apaches, and those who wish they did." My point is that even if you complete steps 1 through 3 successfully, there's no guarantee you'll get to fly the F-35. A lot of Air Force pilots fly cargo aircraft. Not trying to discourage you, just give a little expectation management. Your best bet is probably to consider the Air Force Academy.

Jamie, I've been mulling this question over since you first posted it. As such, some of what I'm going to say has already been said. I apologize for that and acknowledge the greatness of those who said it first. I just don't want this to be incoherent because I omitted a point that had already been made.

There are a number of questions you need to answer in order to make your decision. You're the only one who can really provide the "right" answer to them because "different strokes for different folks."

First and foremost, how important is flying the F-35 specifically to you? If it's an all or nothing proposition, you should definitely go guard or reserve since that's all that unit flies. That's a process in and of itself and I'm not knowledgeable enough to give authoritative guidance on it.

On the other hand, if you want to be a pilot first and hope to get into the F-35, let me give you the perspective of a former USAF pilot whose career path and life in general didn't remain on the vector I intended.

Back when I decided to fly for the military, I just wanted to fly and really hoped to get a (any) fighter. I looked into the USAF and USN. I didn't even consider the USMC because I wasn't even aware they had fixed wing aircraft (stupid me!). I chose USAF because I didn't want to be out to sea and away from home for 6-9 months at a time. It turns out this was the right decision for me... for the wrong reasons. USAF is still going to send you away long stretches at a time. The good part of that is that you'll be on land and not crammed into a ship. Even aircraft carriers are somewhat tight quarters compared to the deployed. On the other hand, you will have the opportunity with the USN to put in to various ports around the globe and get to experience (potentially) more exotic places than even I did. You'll also get to takeoff and land on a carrier, something I wish I'd had the opportunity to do.

It's already been addressed and you've indicated the long, hard road to get to your F-35, whichever branch you choose, so I won't belabor that point. You need to consider the consequences of failing at any point along that path. Would you be happy being reassigned to USMC infantry if you don't make it through pilot training? What about being put into a submarine in the USN? Or being made a finance officer in the USAF? None of those would have been great for me and you have to look at which "second choice" career would be best for you.

The same question applies to aircraft you want to fly. Even if you end up being God's gift to aviation and the best pilot in your class, you're going to be at the mercy of the needs of your chosen service. They may not have any F-35s in your drop at all. (If this happens, I bet $100 the next drop will have a dozen 35s.) For me, I wanted fighters all the way. I would have been okay flying anything, but it would have been severely disappointing. Right now, you say you want F-35s, but you may find you hate wearing a helmet, parachute, and G-suit all the time.

You also may find that you don't really care for the fighter pilot community. In pilot training, I made it into T-38s. After that, I was a T-37 FAIP (first assignment instructor pilot) with a fighter follow-on. I made it through IFF. I made it into and eventually washed out of F-15Es. All told, I spent about 8 years of my life striving to achieve a dream and it got shattered. Then I went to fly C-17s and found that I really liked that community much more. When you fly a fighter (at least in the FTU, which is as far as I made it) you pre-brief for hours on end, fly for an hour or two, and then debrief for hours on end. And those debriefs tended to focus solely on the negatives simply because there's not enough time to also pat you on the back for the stuff you did right. In the C-17, our debriefs were pretty much limited to "so, anybody got anything for the flight" on the bus ride back to the squadron. I'm absolutely oversimplifying here and admittedly never experienced being a qualified fighter pilot, but the laid back attitude of "those crappy cargo pilots" actually fit me better. It reminds me of the old Garth Brooks' song "Unanswered Prayers."

I loved flying the C-17, but ended up hating to operate it. The ops tempo really wore me out. After 5 years of being gone 200+ days a year on a highly irregular schedule, I decided to take a break and go fly the Global Hawk. Now, when RPAs first came out, I was like "no way, I'm never going to fly one of those dang things." When I did decide to go to the RQ-4, I thought it was going to be a quick 2-3 year tour and then back to my C-17. That was over 13 years ago and I'm still teaching how to fly them today as a civilian IP. The point is, you might find yourself being happy in places you never thought possible.

I'll wrap up this post but can actually elaborate even further (you're thinking "dear God, NO") on my experiences if you'd like.