A few questions about this girl. Please help!?

Hi, on my work experience I'm working with a girl. She is SO pretty, great personality! I have questions for you guys regarding stuff about relationships. So, here goes:

I'm deeply in love with her. Although there are many problems. Here goes:

Im 15, and the girl is going to be 18 in September! I know that's a HUGE age gap but I have such a madly insane massive crush on her its not even right.

Or at least I think I do, im going to describe my feelings and can you tell me if im in love with her?:

I try to make excuses to go and talk to her! I cant help but get happy when she walks past! I get a bit twitchy and fiddly, or at least I used to but now I'm way more comfortable around her. I think she is THE most beautiful girl I have ever seen! And I just think she is generally perfect!

Also, she hit me a few times today, as a joke obviously, she had hanger and kept hitting my backside with it! Flirty? Or just winding me up? Errr... We do make good conversation and I've already told her private stuff, and she told me stories too.

We walked to the bus stop, got on the same bus, even though it wasn't actually what she needed to get on. She sat beside me as well. One of my mates has had god knows how many girlfriends so he has experience, and he said that the first step should be to get a hug or get her number, or both.

1. Is the age gap too big?

2. Do I ACTUALLY like her?

3. Does it sound like she likes me?

4. How to get her number?

5.Best way to get a hug from her?

Help