baby food

Ashley • One baby girl, born March 2016. Married. Live in WVa
We started trying to feed our marchie about a month to six weeks ago. She has not handled food very well. I started her on carrots. They gave her a massive belly ache. So we quit those gave it a week. Tried squash. Same thing happen. So now I'm just giving her cereal every couple days. 
Do you think that she's just too young and needs to grow more? 
Or should I try another type of food that would make it easier?