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

I can't see the difference in a 1st LT and saying a SSG get rank to fast. A LT can be in charge of a plt. with less than three years of time, but a enlisted person might have problems. I'm Glade I'm out. That was one of the things I could never understand. How someone who got a commission because they went to college is assumed a better leader than say a man who went to college and didn't get a commission.

wtf I was infantry and didn't make rank till i was in 5, nco rank is leadership,combat,barracks,and whatever else. an insult to all NCOs

Perhaps, understanding the context is the most important thing. Carwood Lipton enlisted as a Private in 1942, rose to become 1SG, and then a battlefield commission to LT before he got out in 1945. James Gavin was promoted to BG at 36.
I was promoted to E-6 in four years and that was a combination of lucky breaks and being in the right place at the right time.

Enlisted in the CG in 1974. Came out of Class A school as a E4, six months later E5, and made E6 a year later with 3 years of active service. Made E7 while aboard the uSCGC Reliance with 5 1/2 years. E8 was at 11 1/2 years. Was I smart or outstanding? No, it was mostly timing. I was in Electronics and most technicians enlisted in the CG instead of being drafted into another service during Vietnam. They were all getting out after completing their 4 year commitment. The Chief mess was very supported and basically told me, you learn more by doing and messing up than watching someone else doing and messing up.

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.