Give them a try, Ric.ror! Hostels are not everyone's cup of tea, but they are very sociable, where age and social class seem less important than elsewhere. I think there is an arrangement where you pay a slightly higher rate as a non-member for up to 3 nights, by which time you have paid the annual membership and get it free, so the risk is minimal. I am 57 and use hostels for walking holidays in preference to b&bs.
The only thing I have noticed is that last year whilst walking the coast to coast, I was twice told a hostel was full when trying to book as a single man, but subsequently found there were places when booking as part of a goup of 4. I suspect this is some sort of covert YHA strategy to exclude paedophiles, but it hurts to have that label attached; if it is the case, the YHA should be open about it.