Obviously don't feel you need to share specifics of how you conceived your son if you aren't comfortable doing that, but one thing you might want to reflect on is that it could be a good deal harder to conceive at 41 than it was at 33-ish.

Now if, for example, you have a known donor able to provide fresh sperm for free/expenses; or if you have frozen embryos from previous IVF, then you'd probably be in with a decent shot. If, on the other hand, you'd need clinic treatment, frozen sperm from a sperm bank, etc then you might find that your odds of success are a lot lower than last time around, and the costs might be quite considerable. So, alongside everything else, you might want to factor in these aspects, and consider what you'd be comfortable with and what you wouldn't.

By 41, the HFEA reckon odds of success with IUI are about 5% per cycle; or with IVF they'd be about 11%, (unless you used donor eggs as well in which case they'd be substantially higher). I hate banging on about age all the time, but just to give some context:

I started trying to conceive on my own at about 37, and have subsequently gone through 1 own egg IVF, 1 cancelled IVF cycle due to not responding to stims, about a dozen rounds of home insemination with frozen sperm (which did get me pregnant twice but then I miscarried both times), and three cycles of donor egg IVF (the most recent of which, my official test date was yesterday and I'm currently, cautiously, pregnant!).

I think your idea of getting some initial tests and consultations done is a good one. You could also make use of the counselling they offer, to talk through your feelings about wanting another child and what treatment options would be the best fit for you.

One other thing to just give you a heads-up on, which you won't have experienced before since you were successful on your first try (which is so awesome!) - you do tend to find that your thinking evolves on all of this stuff. To an extent that's natural, just processing things over time and in the light of new information. When I went into this, for example, I absolutely wouldn't have thought of using donor eggs, and didn't even want to have IVF! But it's also very easy to end up doubling down and ploughing on and on, and so thinking about things like what your hard calling would be financially is definitely worthwhile.

Good luck!

Can I ask how your son feels about not having a Dad in his life? I'm considering this option too but I'm concerned about how they would feel growing up without a Dad. A lot of people who have done it say they are happy but they currently have babies or very young toddlers who haven't been to school yet like your son. I worry that they would feel sad when discussing topics like families for example at school or see other children's dad at pick ups or in the park. Sorry to ask but just wanted to find out from someone living it, how they feel?