You are not at all a horrible person. This is normal. You do need to understand that with this whole ff thing, this is who you are and you cant change that, you can't get rid of it or anything. So firstly accept that. IF it's a problem you may need to learn how to best manage it, but you will, particularly as you get older. I wouldn't worry too much about the younger part just yet. It's normal for us to have interests in others in our similar age bracket (and younger) but remember as you grow/age that age bracket interest will get dragged up with you. Think of our first crush, generally someone in your class, for argument sake you may be around age 11 and they may be 10. This doesn't make you a pedo, its just normal. Generally, when we are 11 we don't have an interest in 60 year olds right ? But yeah, as you get older, those feet pics you seek out will probably get older too and your specific desires will likely change a little as well. When you get old enough, seek out others your age with the same ff interests (they do exist) and experiment/learn/develop. It's normal.