Can I ask why you have waited 6 years? Have you had other frozen transfers in between which have failed?
Also, do you have a partner? If yes, what does he think?
My DS was born via IVF when I was just turned 43. I’m 49 now, he’s 6 and I don’t feel massively like an old woman. But perhaps those 2 years between 43 and 45 are quite significant- I must admit that it might have been psychologically a bit weird to have had a child only starting Reception as I turned 50, whereas you can sort of fudge being “in your forties”.
We did not have any embryos to freeze. I am fairly sure that I would have given it a whirl at 45 if I had had one, but (like you) I had no interest in donor eggs and I might also have been secretly relived if it had not worked. I am now very content with DS as an only and the way that our lives are shaping up-it’s the perfect balance for us. But that’s easy for me to say when I had no option really.
A friend of mine used a frozen embryo and very sadly her daughter was born with a genetic disorder that will require lifelong care. (Nothing to do with her being IVF or frozen, and not detectable in advance, just one of those things). But it’s a stark reminder to me that every new child is a roll of the dice and sometimes sticking with what you have is not such a bad idea. Same goes for the risks to you of another pregnancy.
You need to weigh up the pros and cons of a 2 child family unit (forget about the age factor, you are already in your forties with a young child, this would not change things that massively). Weigh up the pros and cons and balance those against the risk and unknown factors. Good luck deciding, I think it would be hard to not try, but you might be relieved if it fails.