how long before you ask a girl out?

[C7S]

In college, as an engineering student, I had these two girls specifically always inviting me over for dinner where they cooked for me, and I had others inviting me to study with them. I never thought of it as a date or them "asking" me out, especially since the one who invited me to dinner already had a boyfriend in a long distance relationship.

I think you need to give him more hints. I think that he thinks you are inviting him as a friend.