when to ask for her number?

Pics or I can't help.

It depends on how well the conversation goes. If you hit it off, slowly suggest something at the end about how you enjoyed talking, and ask if she's like to talk again by text.

I have no pics



oh okay, also what do you suggest, If she is always with friends? As I have been trying to wait for the right moment ,and she is always talking to her friends.

I have no pics

well you may as well try. Nothing ventured, nothing gained.

I can't find her on social media xD

Do you get along with any of her friends? You could try join in a group conversation to begin with. If not, I guess just try approach her whenever you get the chance and tell her that you've wanted to say hi but she always seems quite busy and that you'd like to talk, or even exchange numbers.

I feel your sexual frustration. It's a hard life when you can't find any pics to fap over.

see I don't know if that is a good idea, if she doesn't like me back then I will just look like a desperate idiot, and it will be so embarassing for me. I was thinking just to casually when I get the chance just say hello and introduce myself, ask for her name etc. rather than saying "I have been trying to talk to you" it won't really work I feel, and tbh I haven't been trying I have just been thinking about talking to her .