Too old to babysit?

I spent the weekend at someone's house watching their two kids while they were in Florida. Getting paid to "babysit" a 12 year old and a 16 year old is about as silly as getting paid to dog sit (that is what neighbors are for). As effortless as it was to spend the weekend with these kids and get paid $200 for it, I can't help but think that I am just to old to babysit. I am very aware of what a snot I sound like right now, however I always says yes when people ask me to babysit, always. I am not sure if it is because I have a heart of gold, I just love money or that I have nothing else to really do (most likely a combination of all 3) but either way I always say yes. I also always regret saying yes the day before I have to babysit. I don't like yelling, I am not very good at playing with my imagination at a pg level, and germs seriously make me sick to my stomach. Conclusion: I am going to be a great mom. It is not that I hate kids, but it is way different babysitting another person's kids then your own or even your own family. People have weird food habits, weird shows they like to watch, weird house rules, annoying animals and a whole lot of other things that you can't really comment on but in fact have to make sure they stay intact while their parents are gone. I am sure plenty of people use to say all the same things about me. In fact, I attacked my babysitter with a pencil once so I was one of those psycho kids that people had to babysit. For real, it only happened once. Basically, no matter how good the money is, how easy the kids are or even the amount of good food people have I never think its worth it. After having the most painless babysitting job of the weekend I have concluded I am just to old to babysit. I am cashing out of the babysitting gig until desperate times call for desperate measures or at least until February 7th because the next two weekends I have babysitting jobs lined up.