Welcome to the Fabulous Fifties. I have never felt so confident and happy as I am now, nor have I ever felt so comfortable in neon yellow jeans (last summer) red skinny jeans (this spring) or JCrew's Minnie Pant. I am 58. Why not try these things? Who is going to tell me I can't?
Yes, I already adhere to CocoLion's list of suggestions for the most part. After a year in Pilates, I did sport some shorter skirts this summer (about the length of bermunda shorts). I do tend to chose more covered than less, however!
I also give my daughters permission to comment on my style (just in case).
Have fun and thanks for bringing up a subject that is important to me...looking good after 50!