Tell her how amazing she is, I would give her my number and ask to be friends, tell her that I'm a big fan of hers and that I've been waiting to meet her, I would hug her and say I love her, take couples of photos with her so I could show it off to my friends, give her a photo of me and her to autograph, tell her that my life is complete now that I’ve met her and lastly, ask her if she would write a song about the guy I’m in love with.
Om this might take a while: be so excited and stuned tell her she is the BESTEST!, hug her tell her that all those guys who broke her heart are stupid to break up with you but youre just to good for them. give her all my contacts and ask to stay in touch. ask how she is so awesome. talk to her sooooo much ask her so much and just love her!!!!!!!!!!!!!!!!!!! and heaps more but NEVER EVER EVER say ANYTHING mean. oh and tell her how UNBELIEVEABLE IT IS to meet her
hug her, tell her i love her alot and then tell her that shes awesome and that i love her album speak now, ask her if she could write a song about me, ask to go on tour with her and then ask for her number and if we could hang out some time