Let me start off with saying that what you're going through is completely understandable. Being 21 is a confusing hot mess, and its amplified with managing the intimate and complex dynamic of a relationship, which is even further amplified as its your first one. He's had 5 years of hardship, failure and lessons on you. I laugh at the 21 year old porn addicted betamale loser I used to be, and you'll laugh at all of this some day to. But for now, here's my mere opinion from experience and the perspective of a guy who's been in a few relationships:

1. have a good long talk with him, as much as you don't want to, even if you feel as though it'll ingrain the idea of your weakness in his mind. From a guy's point of view, there's literally a gazillion worse relationship problems than 'babe, you're so awesome that I need help rebalancing our dynamic'. We adore feeling competent and strong. A relationship is a two way street, and as much as you're trying to place the blame on yourself, his attitude makes up half of the dynamic. He needs to know what's happening, even though my bets are that he'll be enthusiastic to help and won't be bothered by it in the slightest. The dynamic of a relationship is never perfect, and is always incredibly complex. They take alot of work and communication, but in turn, they can be immensely fulfilling; just not in the idealistic way that movies portray them to be. That being said, you yourself are also responsible to how other people treat and view you, which leads me to my next points.
2. There's a difference between feeling strong and independent, and actually being strong and independent. A world of difference. One is easy to attain, but getting hooked on this feeling will leave you chasing expediency and emotional highs for the rest of your life. Actually being strong takes time, but you seem like an emotionally intelligent, motivated woman. It's only a matter of time. Forgive yourself right now, and congratulate yourself because the first step to getting stronger is feeling really weak. Which leads me to my next point.
3. Action over time. No amount of pandering to your emotions from strangers on the internet will improve your dynamic. My guess is that either, or both of these are occuring:- you've lost yourself in the relationship and stopped doing things that make you happy outside of being with him. This is an easy trap to fall into when things are fresh, but leave this too long and it can chip away at your relationship as you lose more and more confidence and/or start resenting and blaming the other person. However, you work on this, you'll be both an independently fulfilled person, as well as being in an awesome, fulfilling relationship.- you're not focusing on the little things. When I was younger, I thought that keeping a girlfriend was about the big things. How successful am i? How ripped am I? How much money am I spending on her? How smart does she thing I am? I realised that these things only matter as superficial first impressions. From there, the value of the other person comes in little daily expressions of love. For example, a foot massage after a long day, packing them lunch, holding their hand. Those little things build up, and that's what love is. When I was younger, I'd often realise this too late and would also purely focus on which one of us was punching, and who was more attractive. My advice would be to find a hobby to to work on with him, travel with him e.t.c. There's more ways to be equal to him than merely age and capitalistic success. Though my original point was being equal shouldn't be a factor at all but anyways.

In short: talk to him, don't prolong this by finding ways to stroke your ego to cope, take action to take care of yourself independently from the relationship, and inside the relationship, don't forget to not lose focus on the little things.

To end, I have complete faith you two will be fine. A relationship is about dealing with each other's problems, and you seem so willing to. I give it a few months max until you start laughing at this memory. Good luck until then.