Firstly, I'm sorry you've had what sounds like a very traumatic experience.
An unplanned pregnancy can be so very stressful, make us panic, and push us into decisions e.g. termination we later regret.
It is very hard when you are in the thick of it to take a measured decision and think logically; because when considering termination there is a cruel time pressure where we have to make a horrible , life-changing decision as quickly as possible.
If this whole experience has made you realise that actually, you would like to try for a third, I would genuinely wish you the best of luck TTC.
R.e your age, obviously it is harder, ( but clearly not impossible !) to conceive in your late 40's.
But you would certainly not be harming anyone if you gave it a go, and if you were to have a baby at 47 ; the child would have grown and graduated university before you turned 70, so highly, highly unlikely that you wouldn't see them well into adulthood.
My friend's mum was 47 when she had her her, ( only child, IVF conception), and now at 30 they are and always have been incredibly close, and enjoy holidaying together a couple of times a year. They have a close relationship and my friend has never felt disadvantaged by having an older mum. '
Also, social services regularly allow people in their late 40's to adopt all the time in the U.K, ( I know of couples in their late 40's who have been approved to adopt young children). Adoption requires careful SS assessment, so clearly they are confident that parents in their late 40's are able to see children into adulthood, or they wouldn't be approving people in their late 40's to adopt.
I would also not worry at all about the age gap between children. Society seems to tell us that the ideal age gap is two years between siblings, ideally conceived at some point in a narrow window when the mother is between 30-35. Real life is not like that, and many people have a great bond into adulthood with much younger siblings. My boyfriend's older brother's are 41 and 43, ( he is 28 and was very much a surprise). He is very close with his brother's and enjoys seeing them, and because they have always been at different ages there has never been any sibling rivalry.
If you can cope with the biological reality of TTC whilst acknowledging that at this age you may not be able to conceive again, I see absolutely no reason why you shouldn't give it a good go and I would genuinely wish you success if you went down this route.
My own experiences are only that anybody I know who has had older parents and/ or large sibling age gaps all seem very happy and well adjusted.