When we first started talking she said that she wanted to keepit a secret from our collegegroup now...?

she's the one that told first. Why? She also said that she isn't ready for a relationship but we talk on the phone 6 hours a day. She is very infatuated with me and I her. How long should I listen to her talk about how she's not ready before I give her an altimatum,? (we start acting more serious or I pursue someone else) weve know each other for two months but have been crushing for one/