Well, guess you guys love that. I stopped reading this one like 60 episodes ago...patience does pay off for youall, good for you.
It's a Japanese romance manga. Nobody sane waits for actual sex to happen. They waffle about in chastity forever, usually. That it actually goes there is just a nice surprise on top of a very entertaining story either way.
With the amount of sexual tension that she has built up over these last 100+ chapters can you blame her? It's a wonder she didn't just immediately explode upon touch.