Turning 21 soon and feeling behind in relationships

I'm gonna be 21 in a couple of months, and I've been having some major insecurity about being a virgin and never having had a relationship. I've been quite shy and reserved always, which doesn't help me get out there. Though I feel I'm sort of good-looking and am working on confidence, this feeling of jealousy just won't go away each time I see other people in relationships. And I always feel like every I girl I see has a bf already.

It makes me question if I'll ever find somebody in life. I know this mindset isn't helpful to me , but i find it difficult not to compare myself to others.

I'm trying to focus on self-improvement and becoming more confident, but the jealousy and fear of "never finding a girl" keep pulling me down.

I'd appreciate it if anyone could share any advice or experiences about how one can go through this and start working on themself. So, how could I let go of the jealousy, build up confidence, and stop feeling that I'm running out of time?