While some girls who lack or had intermittent father figures can become attracted to older men looking for a "daddy", that doesn't sound like what's going on with you from your post. You have two father figures - your dad and stepdad - and you seem to get along with them and see them frequently enough that they still have some male influence on you. I wouldn't sweat that if it doesn't feel right to you and doesn't resonate deep down.
Now, as for being attracted to older men... that's pretty common at your age, especially if you feel more mature than your peers. It's normal for teen girls to find teen guys kind of childish and dorky -- girls tend to start puberty earlier and mature a bit faster in adolescence than boys, it's all down to physiology and hormones. So, it makes sense that you'd be attracted to men that are more mature, more stable and (hopefully) out of that phase... they feel more "equal" to you.
Unfortunately, some men don't outgrow that phase, or are attracted to younger girls for control reasons. It's okay to be attracted to them, but it's not okay to get involved with them in a sexual relationship - and it's illegal in most states in the U.S. (other countries have different laws, but it's still wise to be careful). Remember, that even though you might be way ahead of the pack, you're still not done developing yet. The parts of your brain responsible for good judgment and sense of self aren't fully formed yet... getting involved with someone older can cause problems with your development if you're not careful and they don't have good intentions.
Before you dismiss this as some old fogey who doesn't understand your situation... I may be 36 now, but when I was in my teens I had a few relationships with older men that did damage my personal growth and left me feeling shameful and guilty for years. I wouldn't want to wish those feelings and troubles on anyone. Just take care of yourself and try not to get too swept up in the romantic dreams and hormones - you'll thank yourself later
It is better to be hated for what you are than to be loved for what you are not. --- Andre Gide
Selfishness is not living as one wishes to live, it is asking others to live as one wishes to live. --- Oscar Wilde