I have a 4 year old, an almost 3 year old, an almost 1 year old and am 16 weeks pregnant with my 5th child (eldest daughter is 12 years)My youngest will be 16 months old when baby is born, so I understand your concern! I think that having kids closer together, although may seem harder is actually not too bad, as you will probably find it tough in the first weeks, you will slowly settle into a great routine with the both of them! The benefits are that as they grow together they will have a playmate in each other, as they are close in age, my 4 year old and 3 yo are best friends and am hoping the same for my youngest and new baby too! You just need plenty of support in the early days! My only advice would be as soon as baby is born, try as best you can to continue with same routine for toddler as before, I found that the baby is the easiest part, as in the beginning they do sleep alot and do give you plenty of time to spend with older child, if older child feels things are changing, then they may change aswell, try to keep things as before!