My guy friend is so cute I have a crush on him

I always though my guy friend was cute but he always had a girlfriend and he recently broke up with her and has been super flirty with me. I don't know if I should act on it because I would feel like a rebound. My other friends think I'm crazy because I always liked him but feel like he should take some time to morn his last relationship they were together for 5 years. I got a text from him today asking me to go on a official date. I'm not sure if I should do it what do you think?