Doing something you love is important.Excellent ideas already put forward by other Gransnetters! However, unless you are certain that you will be financially secure for ever, it may be worth getting some/updating formal qualifications - in whatever area of interest is your choice - that will help you to help yourself in the jobs market if ever things go wrong in your life.N.B.if you are limited to one geographical area, don't pick something where opportunities to use these qualifications are far and few between!
I have a friend who most people would think had had it all - but suddenly lost everything in six months through no fault of her own (death in the family, a long-term illness, collapse of a successful business after partner ran off with the profits).
Because she had few formal qualifications, when the chips were down, what she could earn as an employee was minimal.She worked full time five days a week and two half days at weekends for six years in order to pay the bills - and another five years beyond retirement age.
I myself retrained in middle age after redundancy. Best thing I ever did. Really interesting and stimulating course/ people - and likewise job opportunities afterwards. If your skills are up to date, and your enthusiasm matches that of a younger person, no one cares how old you are!