Being 29, you're certainly not too old to be trying for another one I'm 27 and only just about to have my first bub. So you have plenty of time (as you said).

I think the world will always be what it will be iykwim..... I think as long as you can both afford to raise another child, then why not.... I say go for it when you feel ready

As you even said yourself, the yearning for a 4th child will never go away..... so I think you know what the answer is And only worry when the sh*t hits the fan LOL as it may never happen iykwim? don't put things off in life, its too short.

We'd love 4 babies too! My DH is already talking about ttc #2 he can't wait!!