Hi Ruthie, great to see another returnee to cycling.
My advice is to buy yourself some good cycle specific clothing. Having the right kit makes riding easier and more comfortable. I saw a poster in a Lake District walking shop which said "There is no such thing as bad weather, just the wrong clothing" That is true to cycling too.
In the first instance look after your three contact points.
Hands feet and bum.
Gloves or mitts with a gel palm isolate you from some vibtation, keep your pinkies warm and should you be unfortunate enough to fall off your hands are almost always the first part to hit the ground. ( I was that crash test dummy

) so they will be protected too.
Padded shorts or underwear, protection and comfort for your 'sit bones' will make the bike more comfortable and allow you to ride for longer.
Less important but a good buy are cycling shoes, you can get them fairy cheaply. Something you can easily walk in as well as ride in is best. The soles are stiffer and transfer your effort into the pedals which bendy trainers will never do. Also many shoes have lace covers to prevent the old lace in the chain mishap. The cause of several of my early crashes.
Cycling plus magazine has articles and adverts for many of the clothing brands. Sue my wife, loves Corinne Dennis clothing.Great quality and fit.
WWW.Corinnedennis.co.uk.
To meet other like minded folk you could try the Cylist's Touring Club(CTC) They do day rides for all abilities, insurance, holidays, their own shop with member discount loads of other events including The York Rally each June.
www.ctc.org.uk and
www.CTCshop.com Their bimonthly mag is one of the best. Look forward to seeing you on a Charity Adventure ride.
Hope this is of use. Happy riding

Andy