My 50’s have been eventful. I’m 56 now.
I actually can’t remember how I was feeling in the run up to my 50th but my youngest dc was 10 so a similar age to yours. I have 4 dc altogether, and 3 of them were still at home so life was busy. My dad died that year, we were very close and it knocked me back but I had distractions with the dc, plus Dh was ill.
When I was 52 Dh died (also aged 52). Don’t really remember anything much else about that year except it was hard and horrible and I wanted to die too :(.
When I was 53 I reassessed my life and realised that all my friends, though lovely, were in very different places to me, and that my life was becoming increasingly smaller. In an effort to change this, I applied to BA to be cabin crew. Never for a minute thought I’d get past the initial online stuff but I did. I had a conversation with my dc because, if this was to work, they all had to be on board. They were. I got invited to an assessment day and nearly didn’t go as I was terrified! I did go, and I got accepted.
Absolutely loved the training as it was exciting (mostly - hard as well though). Made some lovely friends even though I was by far the oldest on the course - by decades! Got my wings, started flying - and hated it! Won’t bore you with the details but I really really hated it and I left.
I felt like a real failure but then people kept telling me to re-frame it and look on it as something I’d tried, so that helped enormously.
When I was 54 I completely unexpectedly met someone. I knew it would never be a long term thing - Dh is a hard act to follow - but it did my self esteem no end of good. He was younger than me and for some reason found me irresistible and I had the best sex in a long time (Dh had been ill for a long time). We parted amicably after about 18 months and we’re still in touch now and again.
Also when I was 54 I got a job working at a charity which I absolutely love. It’s low paid but it’s low stress and I feel like I’m making a difference.
I’ve also been volunteering for another charity for about 6 years, but in the last 2 years, I’ve become much more involved with this, and again, this feels like I’m making a difference.
So - my 50’s so far have been have been a mixed bag. Some awful things have happened, some lovely things have happened, some unexpected things have happened, I’ve made new friends etc. I think the point of this ramble is to say that please don’t write yourself off, or be sad at your advancing years. As others have said, it’s better than the alternative, and there is still so much out there for you to do and see and experience. You’re going to get older regardless so don’t fixate on the numbers. I bet most of us still think of ourselves as still in our 20’s in our heads - run with that idea (in an age appropriate way!).
Also - there was a really interesting thread on here a few weeks ago called something like “how do you feel if you are in your 50’s?” Might be worth a read!