Hey there....My youngest son and my daughter are only 13 months apart from each other. My son was only 4 months old when we got pregnant again, with our daughter. I had no complications and NO problems, other then stress from an unrelated outside source (my husband's ex gf was causing major turmoil). Other then the stress from that, I had a great pregnancy. And giving birth was a snap because I had just done it not so long before that! The only thing that stressed me out in the beginning was all the diaper changes....it took a minute to get used to, but once I did, everything was a snap!
And now, my youngest son and my daughter are best friends.....partners in crime...they do everything together and really care for each other!
I think you will be fine, and good luck!