I'm 24, didn't start working out until after Highschool. I was a complete string bean (141 lbs, 6'0). Once I started going consistently and and eating right I bulked up to 190 lbs and after cutting I'm currently sitting at 175 lbs. I never really had too much trouble getting girls when I was skinny but in my experience the added muscle mass got me some more looks and comments from both males and females.
Really all it is is boosting your SMV and confidence. Its one piece of the puzzle that makes you more attractive.
I find that girls prefer the "ripped" look more so than the "bulky" muscular look.
After that it's up to your game.
The best part about it is, girls who like to workout also like men who workout as well. (And girls who workout have great bodies)
After banging a chick I put my pants on but keep my shirt off and grab some refreshments lol, and you can clearly see them checking out your hard earned muscle
Feelsgoodman.