E6 in 3 years? Is there such thing as making rank too soon?

Chief, I am assuming you're an initiated Chief and not an E-7. I'm all for encouraging my people to make rate; however, hands on experience and leadership trumps book theory. When I see a red strip Chief it tells me either he/she had time 'afore the Mast, or hasn't quite figured out where the Head is. When someone says, "Go ask the Chief." your response should not be "I don't know." You're the person who has seen and done things that are not in the books. Gold Stripes demand respect. I believe there should be mandatory time between rates, just as officers do their time between rank. Time means experience tried and true.

As some others have pointed out, it depends on the individual. I made SGT in 25 months. I had been serving in Team Leader/Squad Leader positions since I was a E-3/PFC. I went to the E-6 Board as soon as I met Time In Service. Unfortunately, I spent two years on the promotion list. Infantry promotion scores were maxed out at 998. I was always promoted early, and I was always already serving at the next rank. I had some very good examples (and bad) and some great mentors that helped me to be a better prepared leader.
I remember after DS/DS, the Army did a VERA/VSIP (early out). They were targeting E-8 and E-9, but they took just about every application, and it created a big void in E-6 and E-7. As a 1SG, I had E-6 PSGs and E-7 PSGs who didn't/couldn't write NCOERs, Counseling Statements, or Awards. I can't count the number of times I had to tell PSGs and their PLs that they were not going home until the required NCOER, Counseling, or Award was turned in and approved by me. Fortunately, the CO and XO backed me up every time a Lieutenant went to them and complained that I was being too picky.
I wouldn't accept NCOERs with no bullets on the back page. As I explained to the Platoon Chain of Command that they know the soldier, and the NCOER is what will be used to get SSGs promoted. DA promotion boards only look at a file to make selections. Same for awards, I had to train them to put in quantifiable statements to justify awards. Explaining the how's, why's, and types of counseling to an E-7/PSG seemed ridiculous to me, but they didn't have the experience or knowledge, even if they had been to ANCOC.

This must be Army because in the Air Force there is a minimum require of 4 years TIS to be promoted to E-5 and then 2 years TIG to be promoted to E-6

Too quick? Navy Band members start at E-6. That’s pretty quick if you ask me. I would have made E-6 but my advancement date was a month after I got out. They tried to use that to get me to re up. They offered it to me at the reenlistment date. I turned it and $10,000 and choice of duty stations down. Mh wife said if I reenlisted she would leave me. I liked her more

Rank isn't based on merit so it doesn't really matter.

I knew a E-9 in the army and he only been in 9 years. It is all about the MOS and the demand

2.5 year second class here. I missed 2nd at 2 year mark by .01%. if I had stayed in the Navy and made e-6 my first try I would have made it in 5.5years... Fuck that noise! Without a lot of training and experience at being work center supervisor(3m boss); A LPO/LPO; specific in rate related job supervisor; and I would have had to get my Surface warfare pin.

Absolutely. As a FCPO (First Class Petty Officer, for oyu non-Navy / CG types), or any branch equivalent, really, one would be expected to know their job and how to lead / manage people. It took more than 3 years just for me to get my head out of my ass as an E3/E4.

Sure, someone could have their head on straight, but they don't have the seasoning to be that salty yet.

My answer to that is Yes and No; it depends on the person. Either way, it’s a challenge…and it’s supposed to be. How one positions him/herself to respond to the challenges can be the difference between a successfully progressing career or pure hell.
I’m not boasting about my successes but this is applicable to the topic: I made CPO (vice E7…there is a traditional difference) in 7yrs, 11mths, 29days; made everything 1st time up including LDO 0-4. Now, with that being said, I was 24 yrs. old when I enlisted so that tells you something about my maturity level as I “rate grabbed” my way up. I had an agenda: I made up my mind from the start that I would remain in service long enough to retire. I also had the frame of mind to consult with some very good Career Counselors who provided the salient guidance I needed to keep my head in the game but low enough to not get it “shot off”. I took the position that since I was going to do 20 (actually did 25), I would pursue the route that would give me the fattest retirement check...period! But, along the way, as my parents taught me, with one mouth and two ears, “you need to listen more than you talk”. Even as rate grabbers, boot chiefs or butter bars in the wardroom, there are folks that have your best interest in mind…if you’ll listen to them. Sure, sometimes you have to separate the wheat from the chaff (a.k.a. BS), but that’s part of the learning curve or curve ball; it depends on your mindset when you step up to bat.

Maturity level is key. Can one handle the next level properly.