I'm 52 and childless, though married. The majority of my friends are my age or older (up to their 70s) and also childless, and are mostly single for various reasons, including being a widow, preferring just to date, or just not being particularly fussed about having a partner.
When I look at them as a group, what I see is a wonderfully diverse group of capable talented women with wonderful friends, who are living varied lives but all very much on their terms. Of course, there are glitches (show me a human who doesn't have those) but on the whole they are leading rich, fulfilled lives.
To give you a snapshot :-
Widow, 60s. Runs her own business (very specialist in the entertainment industry). Highly regarded. Travels all over the world, often at short notice with her work. Also finds time to run a small charity in her hometown, be an expert gardener, have two lurchers, and be a superb dowser.
Single, just turned 60. Retired from BT, noted local amateur historian, keen traveller (just off to New Zealand), ninja chutney maker, keen crafter and baker, chair of school governors.
Widow, mid 60s. Just retired from a specialist HGV fleet transport role. Does voluntary week weekly plus is organising big community festival later this year. Has travellled extensively including doing VSO in Ethiopia.
Friend, late 40s, single, never married, enjoys dating. Just nursed her father through his last illness while holding down full time job and going through breast cancer herself. Keen traveller (planning a couple of UK short breaks with me later this year) plus milestone birthday meetup in NY next year.
Friend, early 50s. Has lived and worked all over the world and is currently in UK, in senior management role in energy industry. Highly regarded dog trainer with huge amount of friends in dog world. Has represented her country in dog sports and is likely to adopt high level team coaching role shortly.
Hope this helps to remind you that being single and/or childless shouldn't be a barrier to an enjoyable life, with plenty of friends and meaningful activities.