A guy with a small dick would be great. Easy to suck off, he could do what he wanted to you with his dick and it would never hurt. I don't see a problem.
Smaller dicks get hard even as they get older. Bigger dicks get floppier as they get older. Also, they grow more. Typical 3 in flaccid gets to 6 whereas a 5.5 in dick grows to 8. And won't stay hard like the 6 incher. I also find that floppier bigger dicks are easier to control where as the smaller dicks often belong to stronger more masculine guys. Of course, this varies.