Am i jealous of my gay friend?

okay,..so the other day my friend,lets call him (Alex) told me hes bi and even though im straight,im a good supporter of gay rights, i mean, who am i to judge anyone? I am happy for him. Literally two days after he came out, he got himself a bf and i honestly am happy for him but now..okay, we're only in 9th grade and hes telling me all about the sex he does and how much he loves him. Im not mad tht the sex is with a dude, but im just mad tht hes even having it at all...Am I overacting? Or am i just a little bit jealous tht he can find a bf soo fast and i cant? Also, him and his new bf are trying to get me to go out with anther girl and i really hate when they do tht..How do i tell them politely tht im not into tht without sounding like a homo phob?