It will certainly be very hard to do Access and GCSE at the same time as managing children and a household, and working part-time. Be prepared for a hard, stressful year. However, as Wooderson says, if you can devote plenty of time to maths between now and September, you can get a lot done. If you can discipline yourself to do an hour or two of maths a day over the summer, I think you will be fine. (it will be good preparation for managing your time for the Access course too). Good luck.