I'm 46 years old so a borderline coffin dodger.
Been into crypto for around 5 years

had a mini GPU farm a few years ago too.
There was a study released by coinbase showing that most bitcoiner are between 22 and 35 but that still some people are younger than 22 and some are even 65! So I guess yes some old persons actually use btc, but clearly not the majority ^^
I don't know one, but that's not impossible that some with that age group are also investing/earning bitcoin. Mostly those tech-savvy people, maybe just not a member of this forum and/or not earning through signature campaign.
Coindesk also had their survey last 2015 to know the average number of bitcoin user by age, and there were some recorded who are in between 45 and up. You can see the graph below:
I do think there must be some people above 45 years make bitcoins whether from signature campaign or make some investments.
we have the evidence above, so no more doubt of course
since bitcoin has many advantages that so useful for fast and anonymous transaction, its not just for person to person, some business and company using bitcoin as the currency.
I was almost 40 years old and I just now found out what Bitcoin and cryptocurrency. So I think, people with older age, not even heard of it. So I do not doubt that they will use bitcoin if he would be so popular.