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

I think that for most people making E-6 in only 3 years is too fast especially someone who joined right out of High School. Yes, in 3 years they might have the technical knowledge to be an E-6 but they tend to not have the wisdom or experience to temper that knowledge and how best to utilize it. I am not even sure I would have made a good E-6 with only 3 years TIS and I joined when I was 20.

However, someone who joins in their mid to late 20's or even older depending on their background I can see doing well as an E-6 with only 3 years TIS. They probably have the wisdom and life experience to temper their decisions that they would be making as an E-6.

Let me preface this by saying I went to (or was sentenced to by my parents for being in problem child) to a military school in Kansas for 2 years.
With that said I had a blast in basic. I ended up as 'trainer leader of the battalion' and promoted to E2 and got to stand on the viewing stand for the pass and review at graduation. First promotion 7 weeks in.
Then I had to pass COBET (common basic electronics training) before I would be allowed to advance to my AIT. 4 week course and I was honor student. Promoted again to E3. So 2 promotions in less than 3 months. Did well in 26L AIT and got to permanent party and proceeded to show everyone that I really shouldn't have been promoted so quickly. (I didn't realize permanent party was a posting description and not an off duty (or on) activity)!
So, yes, I'd say you can be promoted to early. Although I may have deserved some sort of recognition for exemplary performance perhaps stripes weren't the best choice.

E5 in 2, E6 in 6, E7 in 10, and would easily have made 8 and 9, but there was a fatass, no PT doing asshole that the uppers would not get rid of which would have opened the only slot for 8 that there was. Didn't want to make waves so they let the pos slide.

Talk to the Musicians, Some of them come into the NAVY as MU2 and MU1. It is a very select Rating.. It is rare to find then aboard ship anymore.

I made E-5 in 26 months and was selected to board E-6 at 4 years but didn’t have enough time left on my enlistment to qualify being sent to the board. I felt a little inadequate as a very young E-5 but fortunately had a phenomenal squad leader and platoon sergeant who took me under their wing and cultivated me into an effective leader very quickly.

I was in the 1980s. I made E-5 in 2 years. I was put in for E-6 at 3 years. I was told I needed 5 years tis to make E-6. I thought that made sense.

we were NCO short, they made tanker SP4s AJs to fill the CQ roster. some needed to be wacked upside the air filled noggin. If that doesnt happen then more power to you brother

That was the problem with the " Shake and Bake" program of the Vietnam War Era. Too much rank too fast and not enough time to season as a leader.

I made E-6 in 5 years, counting reserve time closed 6 1/2, made E-7 six years later, I’m glad the Army let me wait because I was very immature and that time. Sometimes it takes a significant emotional event to wake up and get your career straight

I enlisted when I was 21 and made E-7 in seven years. As a buck sergeant I did let my mouth outrun my brain and learned some painful lessons. When I became a Warrant Officer promotions came on time and making CW5 was on my second look. Having promotions on time gave me the years to gain experience for the next step. I retired with 11 years TIG as a CW5 and was thankful to all the folks that saw the potential, but also helped me gain experience and knowledge to do the job.