As was I, as are most later-in-life virgins. It's a catch 22 at this point. Is he nervous around people because he's never gotten laid or has he never gotten laid because he's nervous around people? (as a side note: my social anxiety diminished greatly after I stopped watching porn.)
I have no idea if OP watches porn and if he doesn't my theory holds no weight. That said, I was in a VERY similar predicament until a few months ago and I might be the only poster in this thread who was also a virgin after 25.
I went through all of the same motions as OP. Started dressing better (reason I'm here), started exercising and taking nutritional supplements, improved my diet, online dating, got blowjobs from strippers, etc. You name it and I tried it on the wild mission to build sexual confidence and ultimately give away my V-Card.
The ONE piece of the puzzle that finally allowed me to break through was when I stopped habitually watching porn. That's what put me in the driver's seat. Anddd my first time was even decent to boot (she had no idea I was a virgin).
I will certainly admit what worked for me may not work for OP, but I'd be truly remiss in not making the suggestion.