Eating

My son is going to be 7 months tomorrow and he only eats purées, breast milk, and formula. My friends baby, who is 8 months, eats actual food! He’s eating pancakes and cheese and other solid foods! How to I transition him to eat actual food? I gave him baby crackers that melt in the mouth to practice but he gags a lot. Is he not ready if he gags or do I have to keep trying until he doesn’t gag?