don't know how to start baby with food

But i see a lot of my friends started when their baby is 5 months old.

I don't want to start hem on food, I'm scared a little bit!

But he is crying a lot these couple days! And want to feed more frequently (exclusively breastfeeding), I'm thinking maybe agrowth spurt? Or maybe he is ready for food!?

I went yesterday and bought a zucchini to prepare a purée. But it was late so I decided to prepare it today. But I woke up feeling like no I should wait until he is 6 months. Lol I'm really confused 

**UPDATE

I prepared a zucchini purée after steaming it. Then mixed 2 teaspoon of the purée with 2 teaspoon of breastmilke. I offered it to him he was interested in the first to spoons ! Then he got frustrated! Then started crying! Then he refused it and his face when I offered more shows that he didn't like it!. I'm not sure what should I do? Should I continue offering the zucchini the next couple of days? Because I don't want to try something else incase he got allergic we can know from what it is.