In that case, first of all you have to be sure that she likes too and is not just being friendly. I take your word that she also likes you in the same way because she has sent some signals your way that confirm that. I think if you just be honest with her and tell her that you’ve been building courage to talk to her, she will be impressed because you are not the type of a guy that goes and talk to just any girl. You wanted to talk to her and you made an effort and gathered some courage to talk to her. I don’t think she will be offended if you simply ask her to join you for lunch. Say it in a sense that you two just want to have lunch, don’t say it as in “let’s go out on a date to have lunch”. The words that you will use will really matter a lot.
HSAP lollll…sorry, I found this funny “if the answer is yes, eat all of these chocolates and next time I want to see the box empty” 