Really, I would choose to be myself. He needs to know who the true YOU are, not another that in a future he'll figure out is another person that was hiding his REAL personality.
Seriously, I'm like you (tomboy) and I think that's also a good personality.
Just be yourself ;)

Sorry if i'm a bit late and you've already made your choice. You should never change for anyone, i'm sure if you talk to him then you might actually be suprised he might already like you, just the way you. I hope this help's, but as i said you just need to be yourself! :)

Be yourself

If you don't love yourself, no one else can ever really love you.
Reminds me of a quote from The Little Prince.

"It's only with the heart one can see rightly, what is essential is invisible to the eye."

I say that of you are sure about how u feel about him u should had a friend tell him how u feel. I have done this but It didn't work but I bet it would for u I mean I'm not very poular even though u don't have to be to be in love Or have
a crush and yes boys are SO difficult!! :D deffinitly be it true self I mean if he doesn't like u for u ur relationship wouldn't be true or honest either so that's all I gotta say I guess