Is it wise for me to want a baby at 17?

I'm 17 and in a long term relationship with my boyfriend. The female line in my family has a lot of hereditary problems, and amongst them is endometriosis, polycystic ovary syndrome and ovarian cancer etc etc. My mum married my dad when she was 19 and started trying for a baby straight away, and had to have a lot of fertility treatment and a few miscarriages until she finally had my brother at the age of 26. My grandma was the same and had 3 miscarriages and a stillbirth before finally having my mother at 42(!!!) Me and my boyfriend have discussed marriage and that we both want kids, and are very committed to one another. But, i've got endometriosis and have just had a scan and been diagnosed with polycystic ovaries. This has left me distraught as i have been researching it and read all about the symptoms. I've not been sleeping or eating properly and have just been very down in general. All i can think about is babies, and i am so worried that i may be infertile. In a previous relationship i had unprotected sex for 8 months (yes very stupid of me i know, i've learnt from my mistakes) with no pregnancy scares, so could this mean that im already infertile? i also have very irregular periods, so i got the contraceptive implant put in a year ago but this has only seemed to make my periods worse. I have discussed some of the options with my partner, and I am considering coming off contraception after i turn 18 and trying for a family. I've told him i will only do this if its what he really wants, and he says all he wants is a family with me and for me to have his children. I have discussed it with his mother as she was a teen mum herself having her first child at 16 and she says i should go with my instincts, and that no amount of advice can sway what my instincts will tell me. I am very worried about what my mother will think but hope that she might understand having been in a similar position herself. This is the last thing i thought i would be thinking about at the age of 17. I've always wanted a baby and have always been extremely broody, but i would have never acted upon it until now. Im just feeling very confused right now, but my general feelings are that i would rather have a baby at this age, than leave it until it's too late... i know this has been a very long message but please, any advice is much appreciated and thank you in advance. kate x