Im unsure of how to tackle girls in my uni classes

Theres this one Ive had my eye one but Im unsure how to pull it off

  1. Try to sit next to her in the lecture talk a bit before and when the lecture is over number close I tried this before with one girl and I noticed the iron gets cold once the lecture is done. Is it awkward to number close before it starts?

  2. Catch her as the lecture ends "Hey I noticed you and couldnt go without saying hi etc etc" Seems risky as people probably have places to be so its literally just catching her and asking for number to meet up another time which would be too fast as no chance to build rapport