Help 16 year old boy trouble?

okay so there is this sopre who usta have a crush on me but i was already seeing someone. but now i am single and have a huge crush on him. okay so i have a few questions about it . like is it cute when a girl blushes when she see's you and blushes a lot when you wave? and i am guna talk to him tomorrow but i need topics cause a get really shy around him. and last he has done pot stopped started i mean like i wud never do pot but is it bad to date someone who does?