I can only share with you what I decided, in similar circumstances. I cannot make that decision for you!
I have been told all of my adult life that i wouldn't be able to have kids of my own. Tried very hard to have DD1, and got pregnant the month I quit trying (go figure). I mean, I had finally resigned myself to the idea of not having kids, was ok with that, and blammo!
...so I started wanting another baby about the time DD was six months old! AF didn't return at all until she was 15 months old. Doc told me I should wean if I wanted to get pregnant again, considering my age and my problems and all that.
Nursing was causing me to have a luteal phase defect, and that was why he suggested I wean. I agonized over my decision, but finally decided not to wean my daughter. I knew for a fact that she was not emotionally or physically ready to wean. I had a hard enough time getting her to nurse in the first place, she was unable to nurse her first three months of life! I worked harder at breastfeeding her than I've ever worked at anything in my life before or since, and I wasn't going to just throw all that hard work down the drain for the possibility that I might get pregnant if she stopped nursing. again, she still *needed* to nurse. She's always been a small kid, docs always give me a hard time about that, too. Never been "on the charts" - I'm talking very petite, like 14 pounds at one year. I wasn't about to refuse to nurse her, knowing she may not eat anything else in any given day! She's also a very high-needs spirited kind of child, and when she doesn't nurse often enough, she gets very hard to deal with. I just couldn't wrap my mind around ignoring my child's need to nurse in hopes of having another baby maybe
someday. I felt it was my job to take care of the baby I already had, rather than worry too much about whether or not I'd ever have another one.
I did manage to get pregnant again, relatively easily, without ever once refusing to nurse my child when she asked for it.