I'm going to leave a love confession unanswered
How do you plan on doing that?
I am going to avoid them (the person) for the next couple of weeks
I understand the situation might be a bit awkward.  However, you really should respond to the message.  I'm sure the other person is really anxious waiting for your response!
I told them that I would reply if I was interested... I never specified if I was right then when I was writing the message. To reply or not to reply, is a decision I will take whenever I feel like.
But if the tables were the opposite way around, what would you think? As hard as it may be, the right thing to do is let them know how you feel.