40s isn't ideal, but it's not a terrible time to have kids either. Nobody should stop trying to have kids at 40.
If you're treating your body like garbage, stop doing that and you will have plenty of fun times with your kids.
I know people with significantly older fathers than that and while at all costs you should try to have kids earlier, I wouldn't go so far as discouraging anyone.
40s isn't ideal, but it's not a terrible time to have kids either. Nobody should stop trying to have kids at 40.
If you're treating your body like garbage, stop doing that and you will have plenty of fun times with your kids.
I know people with significantly older fathers than that and while at all costs you should try to have kids earlier, I wouldn't go so far as discouraging anyone.