This reply will probably be harshly judged by many, but I'd suggest virgins to have at least a couple of drinks before having sex for the first time. It'll reduce the tension, the stress, and lower the chances of you ejaculating prematurely.
Anywhore, the real advice is to just go for it. I was so anxious about my first time that it actually took me 4 tries before really f-closing a girl. I didn't want the girl to think that I was awful, so I just didn't fuck the 3 first girls that wanted me to... Don't do the same thing.
As a matter of fact, it will probably be awful. But on the long term, it'll be more experience for you and that's what going to make you better at it.
Oh, and have fun! Don't take yourself seriously!
I remember my first time... I got so wasted at a party, ended up with a girl and I could surprisingly still get an erection. I was so drunk I didn't give a shit about anything, and it was fun. Even though I was probably really bad! I remember falling off the bed and dropping the girl on the floor and starting laughing like hell! Awwww, memories!
Oh, and as for the premature ejaculation. I don't want to be rude or anything but you'll most probably burst early in your first few times, but it's not that much of a big deal. Sometimes, I burst quite fast with my girlfriend (less than a minute) but I can still keep it up after I came for a couple of minutes. Then I just have to switch condoms, wait a couple of minutes and I'm ready for a round 2, which can last 30-40 minutes. But just so you know, it doesn't take much to make your girl orgasm. My girlfriend usually come in less than 3-4 minutes.
Anyways, I'm running out of time!
Hope it helped!