I understand what kind of situation Stanziel is in but it does seem to me you could be arrogant and boost a little too much about yourself.
Remember that when you are in the cockpit, that person would need to work with you and you would need to work with him as a team. If the interviewer doesn't think that you work well as a team then I am afraid very few airline would hire you.
It is good that you are planning ahead and trying to get information from people but try and listen to other people's advice and don't think that people are discrimnating against you either about your age or sex. You are bound to get people like that and the way you reply may suggest to people you have a short fuse. Also, the fact that you thought about instructing but know you stink at teaching doesn't seem like you have thought alot about it!
I have also been 18 and although i am only 20 now, i feel that going to uni is a very good thing. You will meet friends, learn about yourself and work with people.
It's your choice at the end of the day, but I feel just because one person has a go at you doesn't mean you neglect advice from 9 other people.