Cross Product working really weird?

After wanting to make a homing missiles I did some research of my own and found out that Cross Products would work well with homing missiles if you don't want it to automatically point to a target. After some testing I realized I don't know vector math and am confused someone help, I tried to make the missiles slowly aim to the destination but it ended up barely scratching it and going to some other place and if I placed it further it would slow down the rotation speed even though it wasn't even close to being aligned to the destination, here is the code I made so far