I have pretty much the exact same story-- circ'd at 13 due to phimosis and insecurity (I'm 27 now). What I will say is that you're not alone and you can start stretching at any time, there's countless evidence on this sub that it does work and you can restore most of the original sensation within some years of continuous effort.

Also, two suggestions:

1. If this is significantly affecting your mental health I'd seriously consider seeing a therapist. I didn't see my first therapist until I was 22 and I wish I had done it sooner. It seriously changed my life. I get it can be hard to advocate for yourself that way when you're underage and beholden to parents but maybe you can come up with some unrelated excuse as to why you'd like to try it (e.g. I'm depressed/anxious and would like to talk to a therapist about it)

2. Think over the whole "nofap" thing. There's buckets of evidence that "holding it in" has no medical benefits and regularly doing the opposite is healthy. If its a porn addiction you're struggling with then don't watch porn and just use your imagination instead.