While others have probably fallen pregnant soon after having a baby if you can wait it is better for your body. I would suggest chatting to your maternal and child health nurse about this, and maybe your gp or ob.
If I was considering myself I would be waiting for a couple of reasons,
1. to bond with my new little person
2. to allow my body to re-coporate - which is hard to do if your feeding and caring for a little one. not to mention later when you would be reaching the end of the pregnancy and have a teething bub might be awake half the night.

some people can take up to 2 years for their body to get back to a 'normal' state, and the uterous can take about 6 weeks give or take to reduce down.

re menstrual cycle, everyone is different. after DS i didn't get mine back until he was 1 yo, and that was when i cut his day feeds out and replaced them with cows milk.
dd is 5.5 months old, and no sign of my period yet.

if i did happen to get pregnant soon after having a bub, I would still be very happy about it.