I had my third at 40, because we'd always wanted 3, and had larger gaps than we'd ideally wanted due to secondary infertility. I won't lie, I was a lot more tired in having that third baby, but I'm sure a lot of that was as much about having to parent two other children whilst being pregnant/having a newborn. No health issues for either DC3 or I.
I do love having three, but in your situation I'd think really really carefully about trying for a third. Not because of your age but because of your current DC's ages. If your older two were 5 and 3 I'd say go for it. If they're 12 and 10, be very wary.
My eldest was 8.5 when number 3 was born and managing the age gaps (and very differing needs) has been the single hardest thing about having three for us.
Please think, really really think about trying to support older DC through GCSE and A level study and university applications whilst trying to juggle toddlers and sleepness nights. Noisy playdates when older DC are desperately trying to study. Teens trying to have friends over and enjoy themselves whilst you're frantically trying to get an overtired 3yo to sleep. Primary school homeworks and reading practice whilst older DC are asking for help with revision schedules. Trying to find holiday destinations, accommodations and activities that suit toddlers and teenagers is really hard (and potentially expensive unless you're happy just going camping). And that's just the tip of the iceberg.
I'm not saying don't do it, but really really think about it.
It's not just about having another baby to love and another child to mother, and not just about needing a new car and new house. The logistics when you have large age gaps can be tough and can really impact on older DC. Often negatively, in my experience (though appreciate others may have had a different experience).
And absolutely do NOT EVER try for a third because you're hoping for the opposite gender to what you already have. I read somewhere that if you have two of one gender you're 80% likely to have a third of that same gender (I certainly did!). Only have a third if you'd be absolutely delighted to welcome a third boy or third girl.