Solid food

My baby just turned 10 months yesterday and due to the pandemic I feel he is really behind as far as eating goes. I did not want to introduce new foods as I did everything to stay away from the doctor Incase he had an allergic reaction. He is eating VERY small pieces of soft foods, bananas, avocados, etc. I don’t know when to start giving him bigger pieces I am TERRIFIED of him choking! How did you introduce bigger pieces of food? Also how long did you wait in between a new food if at all? My dr recommends 3 days but lately I have just been letting him try whatever whenever.