If I ever set up an OLD site as a business, I'd make it non-ageist.
I'd not allow people to state their age. (As is now the case with CVs, job applications etc.)
In real life, when people meet, you often don't know exactly how old someone is until you've had a couple of dates.
I think online, people could give their life experiences and hence give something away about their age. So if you state you have children in their 20s or older, a man (or woman) is going to have a rough idea of how old you are.
I have not done OLD though one of my siblings has, as have friends and even my own children!
I feel very strongly that I'd not want to put my real age; without boasting, people think I am 10-15 years younger than I am ( these are people like neighbours who have no vested romantic interest- it's just something that has come up in conversation.)
My mum looks 10 years younger than she is, and gets the same comments, and my DD gets ID'd still.
I'd be looking for someone up to 10 years younger or up to a couple of years older max.
But I'd rather not see their age online. I'd want to see a genuine photo and see their life experience and interests. Not a number.