I waited until my baby was 6 months old before starting to wean her onto solids. The benefit of waiting until then is that the baby's digestive system is fully developed so there is less of a choking hazard and they are more receptive to the process and progress surprisingly quickly from purees to solids. It is very rare for babies to be ready much before then so unless they are sitting up, unsupported, it's unlikely they are ready, though speak to your health visitor if you have any doubts.
I think the whole process was so much easier as a result of waiting until the right time, and it worked well alongside the breastfeeding.