You should go and get fitted.

Maybe, but you should go through a fitting to be sure. You never know, you may find out that a different head & shaft may fit your swing better or the T300 head with a shaft other than standard may be better for you.

I’m a 60-year old, 12 handicap and I like the T300. That’s said, get fit and try them all. Handicap index is a good GENERAL RULE for selecting clubs (e.g., higher-handicap players do better in game improvement clubs), but there are many factors that contribute to handicap. Find a reliable club fitter and plan to spend a few hours to find what suits you best.

I have a friend who uses the T300 and is very happy are good irons, however for your Handicap I'm sure that even the T200s are perhaps even better ..

If you can't get a demo, I would try as many as they will let you. Our local shop lets you take a couple demos out to the range for a small fee that they deduct if you buy from them. A 12 handicap and your age don't really represent how well you are striking the ball. I'm the same age and at 16.2, but if it was broke down to tee shots, approach shots, pitching, and putting, I would be around a 5 handicap with the irons.

I think you should get irons that look the best to you. That is, try a bunch of different clubs and choose which one looks the best in the hitting position. Certainly, try all the other clubs, but if all the numbers are close, choose the one that looks the best. You will be living with that choice for a while....