I'm 16, and I have ADHD and Hypochondria. Anyway, I'm pretty sure I have OCD, but I'm too scared to be tell my parents, I feel guilty about having it, and I can't tell them.
-Uncontrollable and unwanted sexual thoughts: I will be on the bus, and see I girl I think is pretty and I get these uncontrollable and unwanted thoughts about having sex with that person. I also have a foot fetish, so if I see a girl with pretty feet I get these thoughts of doing things with them.
-Thoughts of doing extremely rude/harmful things, such as beating someone up, cursing someone out, etc...
-A need to keep rechecking things, this includes homework, making sure my door is closed, and checking doors to make sure they are locked.
-Fear of spiders: I have a HUGE fear of spiders. I am always looking at my ceiling and at my walls looking for spiders, and I sometimes get thoughts about them and then I am afraid to turn the lights off when I go to bed because I think I might get attacked by a spider in the dark.
These are all that come to mind, I feel bad about having OCD, and I haven't told ANYONE as I feel I will be considered mentally ill, or a lunatic.

I have OCD it was caused by a chain of events in my life. OCD can effect us in different ways and with you its sexually.. I'm 16 and I've fort OCD you need help before it progresses.. trust me eveyone has a certain level of OCD but its up2 u as a person to take it upon yourself to do something about it. My OCD drove me so mad I was on the edge of suicide x but getting help was the best thing I did x

1: No, that's sympoms of being a 16-year-old.
2: No, that's a sympom of being stressed/frustrated.
3: Probably not, if that's all you notice. Having an uncontrollable desire to do something regardless of the circumstances would be one thing, but just checking on things doesn't sound like OCD to me.
4: Arachnophobia is not directly related to OCD. I mean, I don't want to be eaten by spiders.

Still, I'm no expert. I do know that there is no reason to feel guilty for anything you have. You should tell your parents your concerns, I'm sure they'll understand and get you checked out by a licensed professional who can accurately diagnose you.
But no matter what happens, you don't need to feel guilty and blame yourself.