Hello linsin: The Skeezyks replied to another of your Threads, on this subject, earlier today. So I don't know that there is a lot more I can add. No you're not coo coo. Perhaps you are a bit reserved by nature. I certainly am. I must say that this guy you've met works very fast, if you only just met 4 weeks ago! The "reserved" part of me wonders what's going on here. But, then, I admit I do tend to be skeptical. Personally I think you would be wise to take this budding relationship cautiously.
But, then, there's the question of why you have difficulty warming to relationships in general. And this is where I think some time with a skilled therapist might be helpful for you. There's no way to know how much of this is genetic & how much is related to experiences you've had in the past. But the important thing is that you're going to need to learn ways of working around your defensiveness. And this is something a skilled therapist could help with. I wish you well...