First and foremost to gain respect. I want to be a bad ass mofo because I want to be respected by guys as equals. I don't like to be made fun of for my weight. I also don't get the proper respect from girls either. I also like to stay healthy too.
You asked her if she wanted to grab coffee. Then you asked if the time worked. Then you asked if the place was okay. Then you asked if she'd prefer tea.
Four questions. Four chances for her to say no. Four signals that you're terrified of making a decision.
Plan it. Pick the place. Pick the time. Tell her where to meet you. She'll either show up or she won't.
Either way, you look like a man instead of a scared little boy.