Maya, I am 32 and still don't really wear makeup, so I don't think I will be of much help, but I did want to add one suggestion. I have dark undereye circles but don't wear foundation because I don't need it, and I find that concealer ends up looking cake-y under my eyes (the solution I always hear is to add foundation, but I really don't want to). The one brand I found that worked really well for me was Smashbox. I know that they have foundation and tinted moisturizer as well, and everything is supposed to be really sheer. In fact, they have a tinted moisturizer that has SPF. Maybe give it a try? They sell it at Sephora, and here is the link: http://www.smashbox.com/SHEER-.....OISTURIZER
Despite the fact that Smashbox is sold at Sephora, I do agree that not all of their salespeople are the best. And I strongly agree with the suggestions to have whoever does your makeup do your entire face and then tell them you want to walk around with it on for the day before purchasing.