Opinion: is it better to ask a friend out sooner or later?

I'd say sooner. More like as soon as you can. If you really have a crush on her, then you should go for it. If she doesn't say no that she's not interested or already dating someone else (you'd probably know if it though) then at least you already asked and won't need to have a build up of anxiety wanting to ask her out.

If she says yes, then good job.

I'd say if you're really that anxious to ask her out, then you should do it now rather than a little sooner.

it's kinda hard to say b/c it depends on the girl. Some times sooner is better b/c if you keep playing the friend role than that's all they will see you as, but you also don't wanna be to soon. But timing is everything and that's something that you have to get a hand on, like when is to soon vs when is just right.

Self-Reflection. Every time i do anything involving relationships, I reflect who i am and ask many questions. Such as. I am right for this girl. Is she right for me. Will it last. Think about her in a rational way. Don't blind yourself because your attracted to her. You could ruin your whole friendship with her by getting into a relationship that isn't serious or for the wrong reasons. After you reflect make your decision. I can't make it for you, or anyone else. =)

Female friends are your friends for a reason. Keep them there. The reason your other female friends have turned you down in the past is because they just wanted to be friends.

Sooner mate, the more you hang around and talk with her the more she would get wormer to you and would say "Yes" easier

sooner!