Should I tell him that something is bothering me?

If you are jealous already and your not going out or even been on a date this relationship is a recipe for disaster! He has lots of female friends and if you two are going to date you need to accept that, and not get jealous otherwise it will never work out and you will drive yourself insane. If you decide to go ahead with meeting him, I wouldn't say anything about this girl, but find out where you stand with him, e.g. dating, friends, relationship etc and find out if whatever it is, is exclusive, of not you need to accept that he may have a number of girls on the go and you will have to deal with it and not get jealous, life is too short for jealousy, there is too much fun to be had. Just enjoy it x