I am a big believer that you dont have to be in your thirties to be a good mum. As long as both of you do the best by your kids then nothing else matters!

They might be close but just remember people have twins and seem to cope just fine

As for the prams;
The double side by side... is easy to push and fits kids nicely, but can be a little tricky in navigating thin shop isles etc.

The one in front of the other seats(i got this one.).... It is really good room wise for kids, storage basket is huge, but it is like a freight train to push..hard work up hills, particularly as the kids get bigger!

The pram with the toddler seat on top...easy to push, good vision for the oldest child, but can tip over a little easier than the lower prams, has no sun shade, no rain cover, and the toddler can't really sleep unless they can sleep sitting up (amazingly some kids can, wish I could).

I guess you need to way up what you will be using it for mostly.
The only reason I can tell you all this, is because all the girls at my old playgroup (were i used to live) had all different prams, makes for a good assessment of the pros and cons.

Hope this helps.