How can I be more interesting with her ? Its like every time we talk, now I run out of conversation. Its not like I stop talking to her after that , I ask her how she's been or what she's doing and everything. I feel like I'm not interesting anymore. So someone help I need more conversation starters or something ?

I have never texted in my life.
If I woke up tomorrow a teenager and had to text my best friend and boyfriend, I think I would die. It's an epidemic of stultifying boredom and banality. It was bad enough in the pre-text cell phone days, when I had to listen to inane conversations all around me.

Next time you SEE your girlfriend, tell her how you want to text each other only when you have something important to say. Tell her absence makes the heart grow fonder. Tell her that it's more fun and exciting and romantic to see her in person with all sorts of things to talk about.

If you have to have little texts once or twice, make them nonsense, funny, or romantic.
I have to go climb the Empire State Building. Back in 4 hours.
Your eyes see the deepest part of my soul.
How do you catch a unique rabbit? Unique up on it.

I'm with Joy. Texting is the dumbest thing that has ever been invented and is contributing to the loss of interesting conversation and honest connection with someone. It is mindless and... well, enough of that. Get a riddle book from the library and ask her a riddle every time you are required to text.

And spell words correctly and use full sentences.