Well, I've had 9 in 15 years time and have not experienced any problems related to how close my children are spaced.
The closest we have are 11months apart. I went in to the OB thinking he would consider me high risk b/c that's what I'd read. He said "no way!" and I went on to have a wonderful pregnancy. The furthest, btw, are 33months apart. I don't know yet for these two how well that will work BUT my first two are 30months apart and it has been a struggle between them since day one. NOW, at 15 and almost 13 they are becoming friends.
Good luck to whatever the future brings you.