Moving in together after a year and a half long distance relationship bad idea?

It could work fine, it could be a complete disaster. Going from one extreme (long distance, seeing each other every few months) to another (living together) can be a shock. You will go from these very long breaks where your desire for each other grows daily, to not being able to get a break at all as you will sometimes feel like you are together all the time. It would be better if you could ease into it, like moving into the same area and seeing each other regularly for a little while before moving in together....but if that isn't an option, then do what you feel is best.