An archaeologist is the best husband a woman can get; the older she gets, the more interested he is in her. Agatha Christie
Surely this is one field where ageism will not flourish! Intellectually stimulating, and potentiality physically stimulating also if you get involved in a dig.
The website for the Council of British Archaeology is a good place to start: http://www.britarch.ac.uk/
It’s also a subject tht the BBC covers rather well: http://www.bbc.co.uk/history/archaeology/
For part time courses: http://www.sussex.ac.uk/Units/CCE/archaeology/programmes.html
And for distance learning : http://www.le.ac.uk/archaeology/dl/dl_intro.html
And a magazine on the subject: http://www.archaeology.co.uk/