I am 41, and have excellent skin with very few wrinkles. except the awful "11" between my eyebrows.
A friend dragged me to an open house a few months back and I had it done. I had a headache for a few days, but within a week my forehead was smooth and looked great. There was a little drooping of my left eyelid, but I think that if you constantly move your forehead around when you have it done it helps.
Also, don't get greedy. I would wait at LEAST 6-9 months between treatments and would also never have two procedures done at the same time i.e. botox and Juvederm. Space things out.
Painful for me, but sooo worth it.