You started off alright. I'll give you some notes from where it goes more wrong:
ME: Ohh that sucks, your phone is probably lame lol jk. -----don't include the lol jk.
ME: I can't believe u drive. You looked young when we were talking. How old are you? --- Don't include the "you looked young when we were talking." Also, instead of asking questions use a statement. Like "You looked young when we talked. Tell me how old you are."
HER: lol ! Awe that's sweet of you lol
HER: How old do you think I am?
HER: Or how old did I look? lol
ME: I taught u were 7yrs old! Haha. I took your number just in case someone kidnapped u i could call help for you. ----- Seven is a bit much. If you would have said sixteen it would have been fine. The kidnapped comment was funny. Nothing wrong with that.
ME: Honestly, i think you looked around 19-20. ----- Don't say "honestly" You're a man who's always honest. Saying "You look 19-20." is fine.
HER: Lol! Oh my gosh haha no
HER: I am actually older than 20 lol but that's sweet of you
ME: Your welcome. ----- You're welcome is boring. You could have bantered.
ME: We should hangout, what u doing 2mrw or tonite? ----- Say "We need to hang out soon. Tell me when you're free."
ME: If you're more comfortable talking with me on the phone that's fine. I don't want to push things on you. -----you're coming off as the manipulative nice guy. And she hasn't texted you back yet so wait for her text.
ME: I'm 23 btw. -----Don't text her when she hasn't been responding.
(2 days later,)
ME: Hey, how's it going? ----- No! No! Write something less boring. Say something like, "You've obviously been kidnapped by a gang of ninjas. Hit me up if you're not yet dead."
She would probably have responded "lol" or something lame to which you reply, "I spent the last day taking karate lessons to save your life. You disappoint me, trolley girl."
Damn bro that was really in depth and insightful. I defiantly agree i shouldn't have said your welcome and kept bantering. Do you think part of the reason why she didn't respond much was because i didn't flirt/tease (set my intention) her during the in-person interaction?