I haven't checked the statistics out so I don't know but I think that you'll find a mixed population in most areas. I have lived in Devon and didn't notice a larger elderly population than anywhere else, though I must say I wasn't actively looking for elderly people!
About 3 or 4 years ago when I was moving back to the North West one of the places we considered was Grange-Over-Sands which has a reputation as a retirement town yet I was pleasantly surprised to find 4 primary schools in Grange. Also Lytham St Annes, another favourite retirement place (or so I've been led to believe) has the largest secondary school in Lancashire, so there are obviously a few young people around!
Small places can change quite a lot, when my in-laws moved into a small village in the Cotswolds (about 50 to 70 houses) about 15 years ago there wasn't one child in the village, now there are loads of children.