mine are 10, 8 and 6. dc3 suffered birth hypoxia and has cerebral palsy, so the first couple of years were very traumatic - and i think my ds, who was 21 months when dd2 was born, has very probably suffered even more as the middle child as a result!
now that things are more stable, i often wonder whether we did the right thing by getting dh's vasectomy done asap after dd2's birth. even dd2 would like another baby, but there was just no way we could contemplate going through it all again at that point.
my point really, is, no-one knows what's going to happen in the future. whatever does happen, you will find your way round it.
i will say, (sn not withstanding) trying to get 3 different children to after school activities, parties, sports, is no picnic lol. this is the first year that all 3 have been in the same school - having spent some years ferrying children to different schools and nurseries (for three years all three were in different settings) it's a logical issue lol!
of course, none of the logistics matters, really, it's your family, after all. but if you get stressed out by the idea of having to be in four places at once, don't do it lol!