Ask a more mature girl to go shopping with you. Not an older person, but your older brother's wife or someone like that. If you don't have anyone like that, go to a good store when it is quiet (like on a weekday morning) and the assistants have plenty of time, and ask them to help you pick an outfit. Go somewhere that is nice enough that the assistants aren't high school or college-age kids. Tell them your budget. Even if it is really small, they should be able to help you. My brother did this at Nordstroms and he got outfits really cheap because of the great sales. The assistants spent a long time helping him out.