I would say this is a personal choice. I would think about how sex may change your releationship and weigh out the pros and cons. Sex can add closeness and intimacy. It can also add complications and dangers, such as std's and pregnancy. There is also the risk of being taken advantage of, such as the guy sleeping with you and then not coming back. I think after a couple months you have a pretty food idea of his intentions and character. With my wife, I think it was like 3 weeks before we had sex. Although I was infatuated and we spent just about every night together after the first few days we meet. I think you will know when you are ready, and if there is something in the pit of your stomache wondering if it is right, then you are probable not ready.