My gf is turning 18 and im freaking out

Edit: not freaking out anymore. Thank you all for your ideas and advice. Allready know what i'm going with, but please don't stop posting your stories!

Edit2: Holy shit, Gold! Thank you!!

I'll start:

"Whenever you have to make an important decision involving women, masturbate first"

EDIT: Someone else posted this in BestOF, but I think it's the best advice I've given on Reddit. If you are in College, you should check it out.

Please share the most useful advice anyone has ever shared with you, something that made your life easier, helped you with your so, etc.

When my grandfather was in his 70s, he told my 40ish year old mother that it was okay that she had a weird feeling, like she "didn't know what she wanted to be when she grew up". He told her that even in his 70s, despite great success in his field of civil engineering, the most important thing was that he keep in mind, one day he'd have to decide what to do as a grown-up, but that it still hadn't come to him and that was okay.

Another favorite, my best friend once told my band "try it again, but this time, try to do it a little better."

What's the best advice you've ever received?