My personal experience;
I'm 31 weeks pregnant and my daughter is 20 months, so she will be just a month short of 2 when the baby arrives. I really wanted them to have a small age gap and as I'm off work I thought it made sense to have them close together. Also as my mother had fertility problems I was terrified of having the same thing so I didn't want to delay the process if I ended up needing fertility treatment etc.
I got pregnant faster than expected really and I am delighted, but to be honest it has been tough. I don't know if its because my body hadn't really recovered from last pregnancy but this time has been much more difficult. All the symptoms I had in 3rd trimester last time occured almost immediately this time. In fact I had sciatica and hip pain before I even knew I was pregnant! I was horribly sick up to 16 weeks, and now at 31 months I really struggle to get around.
Meanwhile my daughter has collected almost every bug, germ or cold going round since september - so we have been almost permenantly ill for months (poor baby). She's also teething and insists on being carried around everywhere. I'm exhausted, and really struggle with the physical aspect of chasing after her.
I'm also concerned that when baby arrives is exactly when I should be starting to think about potty training for my eldest and i feel horribly guilty like I'm going to be neglecting her a bit. This has made bonding with this baby a bit difficult and I'm really worried about the birth because of being away from my eldest, to the point where I think I'm going to opt for a c-section to best be able to plan chilcare (we don't have family nearby).
If I had my time again - i would probably still do the same and I am really excited about having my two little girls close together, but I think realistically if I hadn't been so gittery about trying to conceive again I might have waited another year, even if it was to give my body time to recover a bit more and to time it so my daughter was a bit more independent and closer to preschool age.
Hope this helps, apologies don't mean to sound miserable. Its been a long tiring day!