Sex is often mental for people. If you have anxiety about this, you likely have anxiety about other things, yes? Would you benefit from some general therapy for anxiety? Likely you would. You don't have to say why you want therapy to your parents but talk to them about anxiety in general and get some real help for it.
Along with all the rest of the good advice you have received here, just to broaden your mental image of what counts sexually, I'll add that some women don't prefer the entry of the penis in sex to be when it is a massive, hard-as-a rock boner a la porno film, but like it better for him to insert when he is not quite so hard, and then to have him get harder or bigger once inside. That's because the first entry of a totally maxed-up penis can sometimes be painful to the opening of the vagina, it is naturally closed most of the time and can need a chance to stretch and adapt. A guy who starts with enthusiasm and takes the lady's guidance on what she would like and when, will be able to insert at the most comfortable stage for her, and then things will progress from there.
It doesn't really sound like the problem you're worrying about now will follow you into your years of having sexual activity with partners (your hormones will likely see to it that things stand up like normal). But in the small chance that this self-consciousness persists and you have this issue into your active-sex years, don't worry. It probably won't displease the ladies, as long as you're enthusiastic about them, happy to be there, and clearly having fun.
Annie, just asking, I've been a guy for 67 years and I have no idea how I'd be able to control how hard I was when I entered a woman. It does what it does. If it isn't rock hard, you often can't enter at all, especially with older women because they have a harder time self-lubricating. I'm just wondering, because since I had a pretty botched prostate surgery sometimes it works and sometimes it's just not that hard, and it doesn't and never has gotten hard once I'm inside someone. Never heard of that, I guess. Just curious. Maybe something to learn there. I guess my point is, from a guy's perspective, it has to be hard to get past the defenses, so to speak, if you get my drift.
I think something specific I keep feeling anxious over is getting one while standing. I didn't cum for about a week now, so I feel a lot of sexual tension. I can get really hard in other positions. (Sometimes it's unexpected since it's been a while for me.) Lately it can get up all the way if I'm standing, but it's usually if I have clothes and maybe it's just not as easy to focus on how hard it's getting. I tried watching/listening to porn before while standing naked to "test" and if I was calm or distracted it worked fine. (I quit watching it a while back before this problem and I realize it's just not that calming or healthy, so I think it wasn't a good idea.) I talked to myself before and closed my eyes and that worked a few times. I'm still noticing it get up in the shower (without me wanting it) and it stays weak if it does. I can tell I started pressuring myself with "trying", so I stopped and hope it makes me feel better.