Assalamualaikum bro - Welcome to TTI and Islam - Congratulations!
Dont worry about your girlfriend.
Dont worry about anyone for now, except yourself and how you can INCREASE your own knowledge about Islam.
If you attempt to shove Islam down one's throat.... then there gonna spew it out. Try to lead by the Quran/Sunnah and follow Islam truly in your heart.
The other thing is, Shaitan will most likely LOVE to spear-tackle you off the Straight Path, so be careful of his whispers.
If you have any questions which bug you like wild-fire man, post them here.
Remember also that when you sin (we arent angels) repent.
Learn how to do salaat (pray).
May Allah subhanuwatala make things easy for you and grant you patience and self-control

ameen.