If you said no that night, then THAT was your best choice. Anything like this should not just be done because it's "convenient" or you "had the chance". It should be done when you're ready to do those kinds of things. Likewise, things like STDs and the like do exist, and there are quite a few STDs that can be transfered from acts of oral sex, so that is something else you should bear in mind before doing something more.
Remember, you're young and you have ALOT of things ahead of you. Don't do anything now that you would regret, because you have plenty of time to try them when you are sure you are ~ready~. If you ever have any doubt in your mind, or you are scared that things may go too far, then I wouldn't do anything more.
It's all about your comfort level and what you want to do. In terms of him not doing anything while your parents were out, that could be many things, and I don't know what prompted that, if you are worried. Maybe he didn't want to pressure you, maybe he wasn't interested, maybe he just wanted to hang out... That could be anything.
Either way, I still think you made the best decision by leaving it where you did. If at any time you even ~think~ that the answer is no, then I would stick to it. It's when you misjudge or ignore your feelings that you will later look back to regret something even more.
