You're leaving the actual world and now entering girl world. Don't do it. Well, if you want to possibly loose a friend but gain a boyfriend sure. But I mean guys are only temporary jar? You could go to your friend and ask permission... But I've seen this happen too many times, she will say, sure go for him, but in her head she will be like- oh no she didn't, especially if she called dibs. (I feel like Im in mean girls- lmao)
In all honesty, (real world) do what you want, you only live once, and I'm sure your friend will be happy that you got this guy...