I wanna impress this girl...

This is sooo pedantic, just quit this nonsense and do some revision.

Go to the gym for yourself and not to impress some girl that you don't even know yet. Instead of trying to impress her you should actually go and talk to her. if your too shy to talk to her in person then add her snapchat and send a message on one of her stories.

There's nothing interesting or attractive about a little dude that spends time in the gym because he thinks it will impress the girls. That's boring and desperate.

If you want to impress her with your physique, it shouldn't be an end unto itself - there should be a point to it. Like say for example you got really into rock climbing or skateboarding and did loads of gym nonsense in pursuance of that, then you have something to talk about and a "healthy" lifestyle to go with it.

If you're just going to do loads of reps and walk around like some kind of shredded hobbit, that's a loser move.

Unless you meet a wizard you can’t make yourself taller

You don't need the gym to approach a girl, you need to just go for it. Practise it over in your head if you need to or if you really can't do it in person, just slide into them dms. If you do want to bulk up still, then eat protein like fish, meat etc and have some protein shakes. No point doing weights if you arent eating right. Good luck.

Not saying you’re done growing, I’m saying there’s nothing you can do to accelerate or increase the process

Well not to be glass half empty but ur 17 and I dont think ur gonna grow a lot.

But, there are diets you can google if u wanna eat healthy

that's a good point , all the girls in my college are really shallow though like i'm not even joking they only care about the fit gym boys and no other guys , everything else to them is just a bonus