How exciting for you! Except for the leaving the kitties part.

But trust me, they will not forget you. I left Tubby at my mom's for 4 months while I tried a venture down in Florida years ago. And the second I came home Tubby was all over me letting me know that he missed me terribly. He didn't even pull the "I'm mad at you so I'm going to ignore you" thing. Slept with me the first night I was back even.

Three months isn't really that long, and it'll be over before you know it and you'll be back to your babies.