I feel that you are thinking too much about it and not actually doing enough. Why didn't you set a date with her instead of asking her to let you know when to go out for seafood? You have now left the ball (so to speak) firmly in her court to ask you out and a lot of women are not comfortable with that. I reckon you need to speak to her again, ask her if she will come out with you on such and such a date and if she says she cant make it, suggest another day. If she doesn't have another day available or doesn't respond by trying to resolve the date issue then forget it, she doesn't like you like that.

Also, you have left it a bit late to start making moves on her. If she liked you at the start and didn't get any response from you their is a high chance that you have been moved to the friend zone of her heart and if that is the case then it will be likely you will stay there.

But please try, don't ever go through life saying you wished you asked that girl out because the worst that could happen is she could say no. If you ask her out at least you can say you tried. She might be wondering why the marry are you having the sudden interest in her if you didn't even look her way for 2 years!