I started DD when she was almost 6 months. Her first food was banana. DP wanted to start her at 4 months because she was staring at us when we ate. She had greats head control and was mouthing lots of things. But she showed as much interest in everything else we did. She was just becoming more aware in general.
Now she eats steamed vegies, cut up fruit, chunks of meat (gets little bits off but mostly just gnaws on it). I also make meals in the crockpot for her and store the in baby food jars for when we go out. These meals include things like shredded chicken, oats, barley, lentils, herbs, spices, fruit and veg. She chose BLW (wont let us feed her) and loves her food.