Baby's first food help.

Hi everyone! My little bun turned six months. No teeth yet, and she can't sit up by herself yet (but does well when supported). My pediatrician told me that I need to start feeding her solid food "or else things can go bad." It's a little confusing because I've been hearing that breastmilk is all a baby needs up through the first year of her life. Anyway. I tried feeding her solids. First it was mangoes, then it was bananas, then Ella's pears, peas, apples, and broccoli. She has gagged on every one of them, and actually vomitted from the bananas (I mashed them myself). I think she may be too early to eat solids. Any moms out there have a suggestion on a solid that won't make the baby gag (from taste)? Or, thoughts on waiting it out until she is older to have solids?