Guys, at what age do you think a woman stops being hot and too old to have sex with?

I'm 33 and I'm still good looking and have a great figure (no kids and great breast implants). However, I'm not nearly as hot as I was when I was 24! I get very depressed about this. I'm attracted to guys in their early and mid 20's. I know I can easily pass still for around 28! I know I sound shallow but I my self-esteem has always revolved around my looks and sexuality. I'm trying to work on developing other interests so I'm not so consumed by this. I'm also going to start working out. I reassure myself that women like Demi Moore, Sara Jessica Parker, Christie Brinkley, and Pamela Anderson are all 40 or older and are very hot. PLEASE DON'T REPORT THIS QUESTION simply because I said SEX. This is a legitimate question and not perverted. It is also daytime so kids should be in school. I will simply ask it again at another time. Please be kind, I'm depressed and need feedback and I know alot of other women feel the same way I do, right?????????