Fifty! Pfft!
You're a baby still!
I wouldn't think twice about meeting with a fifty year old guy.
I often get the "You don't look 39" statement from a lot of guys, too.
I'm not in great shape, but I think my face is OK.
You're right, though: online cruising is much harder. I am summarily rejected by many just because of my age, which I find hard to understand sometimes. Some guys have cutoffs of 36 or so. Ridiculous.
For me, sex is on a case by case basis -- if we have something in common, I'm all for it. Age and race and shit aren't important. HOT SEX is.