No, you are not small. You are average.

A lot of men ejaculate quickly, especially when they are young, and especially their first time. That's normal.

Many people have tried to change their sexual preferences. It usually does not work. That's ok though. There really isn't any good reason to try to change. You can be attracted to whomever you want. If you are attracted to men sexually, but are not comfortable dating them or being open about it, that's ok too. A lot of men, straight, gay, and bisexual, like anal stimulation.