Outsider85 wrote:
When would be a good time to ask her for her number?
Do you
know she's single?
I have not gotten from your posts that she's any more than friendly and polite. Maybe spend more time at the library- not in the stalker sense- and see if she willingly engages you in conversation. If not, she may not be interested. She could be married, or gay, or does not believe in mixing with patrons other than in a business like way. You've come across as polite and friendly. If she wants to approach you, she will. But it's too early to ask for her number. Only ask if she exhibits obvious interest.