As long as your baby shows signs of readiness, and is sitting up well, you can try. Most mummies err on the side of caution but you can start trying if you wish. For the first few months can just start with one meal a day. i started with rice cereal with BM. then puréed vegetables and fruits with BM. milk continue as baby’s cues as it’s still the main source of nutrition until 1 year old. 9 months old can introduce more purées during snack times. you can search Solid Starts online for a good guide.