You don't have to include your D.O.B on CV's these days and as people have said unless your advert specified an age range (which has to be for a very specific reason) then there is little you can do.
I can usually work out a rough idea of how old a candidate is based on how many jobs, when they first started work, even certain terminology.
I have employed loads of people over the years, young, old, experienced, total newbies, male, female etc, because the relevant fact was that at interview i felt they demonstrated what I am looking for and would fit the company culture, and so far I have only been proved wrong twices out of about 40 hirings. In fact 99% of the people I have employed for my company are still with us, are top performers and a number of them have been promoted.
I disagree that hobbies are not important, they can tell you a lot about a person. For instance, we have a lady who in her spare time works with young children with special needs, taking them on outward bound courses etc. What this gives her is a great deal of understanding, organisation and the ability to cope well under pressure.
These assets transpose into her day to day role and improve her performance.