Thread: 3 months at gym and still feeling frustrated

Hello! Alex here.
So I'm 40 and three months ago I probably took the best decision in my life in commiting myself to stay fit and strong.
Despite my age I feel very well, full of energy and my diet rocks (I managed to lose about 45lbs in the last year), I learned to count proteins, calories and I love it.
So, with much enthusiasm and 100% motivation I decided to take a membership in a local gym for a year, confident that I'd quickly overcome the fact I always considered the gym intimidating.
I paid 2 personal trainers (!!!) for a total of 7 lessons and 2 routines (total $300), because I started, the first month, in a different gym (same membership) and wanted to start in the right way; I don't regret for the money spent this only shows my motivation, and I was confident that at least it would be good to learn the proper way to exercise.
Now the problem is that after 3 months, I'm accustomed with the gym, and I really like to go there, in a way I don't feel intimidated anymore by the gym per se, but, by the exercises, and the many theories all the people I hear have!
I always feel I don't execute well every exercise, I have doubts about the loads, don't know if I chose the right load and if I'm properly targeting the muscle I want; in many exercises, I have the feeling I'm using the triceps instead of the back the chest and so on.
I'm a perfectionist so I really hate that. I hoped that after 3 months, at least, I had learned the form, techniques, load selection and so on, but to be honest I didn't.
I'm not saying I don't do nothing, honestly I find some good improvement (and I often find some exercise, for example legs, triceps and biceps, targeting very well).
As a perfectionist I hate when some random people correct my form even if I know that's something they do to help and I really love this.
Today a guy told me that for the first 2 years he'd use only machine if he was me, and it's exactly the opposite my personal trainer told me (he loaded my card of dumbbells and barbell).
So resuming I find quite difficult to understand and be confident about the form, plus I hate the fact that I feel that all the people in the gym seem to my eyes very good in training and I feel clumsy.
So can you give me some sound advise to overcome this? It's not a motivation problem, I'm still loving it but I've the feeling I'm not leaving the novice phase. Another thing to say is that I'm skinny fat 21,5% bodyfat so I decided to cut (albeit I'd prefer the bulking phase as I want to get big).
Thank you very much to all the fellows who'll answer.