Yeah, I get what you're saying. You want to know if your friend takes you seriously as a peer or considers you, for lack of a better word, lesser in some way. It's not the kind of thing you can just ask someone, "Hey, do you respect me as an adult or just let me hang out with you cause I say funny things sometimes?" For my part, if I thought someone didn't respect me as well as like me, then I could not be his friend, just as I will not be friends with someone I don't respect.
So how do you find out which category you're in? Hard to say, but does she ever ASK you for advice, rather than just give it? Does she introduce you to her other friends without hesitation? Would she trust you with something valuable of hers rather than inconvenience herself in some way (like letting you use her car to go to the store for her)? Things like these can tell the difference between someones peer and something more akin to an adult/child relationship. And I may be a lot of things to a lot of people, but I'm no kid.
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Everything would be better if you were in charge.