A couple of thoughts. Firstly, there's the talent thing. Folks with natural high VO2max will dominate a TT. If you don't have that, it isn't going to happen for you. Then there's age. You the same age as those with whom you are competing? Equipment is a little bit, but not much. It's mostly power and position and thus power in position. I assume you have some sort of TT bike or road bike modified to TT. Messing with position can get you a little, but only if you can still breathe. Mostly, it's power. You don't say what sort of training you've been doing. TTs, especially short TTs, take specialized training to get fast.
Lastly, if you're finishing well back, your major competition is with yourself. Accept it. Don't worry about the other folks. Just ride for your own pleasure and to see how good you can get. I wouldn't set a goal. Instead, look into training smarter. TT helmet is the cheapest go-fast equipment there is, if your position will allow you to make good use of it.
Put up a photo of you on your TT bike.