World Health Org. recommends starting solid food from 6 months. 5 months is too soon.
When you start solid, try 1 food at a time for 3 days before you introduce another new food. This is to enable you identify which food could cause allergy. Start by mixing rice cereal with formula or breast milk first for bb to get used to the solid food. Then after 3 days, you can add meshed apple (finely meshed). Then after another 3 days you can add meshed banana. I only started mixing more than 1 type of food with rice cereal when bb turned 7 months. There was no rush at 6 - 7months because each meal of solid food was still supplemented with a bottle of milk to make sure she got enough daily nutrition intake.