legumes as a staple food to replace cereal?

After major dietary changes and different trials/errors, I now know that in my diet most cereals are to be avoided as much as possible ( I dont know whether I am celiac disease sufferer or not, but I surely have some kind of strong intolerance esp to glutenous ones).
Being aware of that, I would like to offer legume-based meals to my toddler daughter (2 yrs)rather than the cereal-based ones she had so far . She loves whole wheat and spelt pasta, but she just likes beans, lentils and chickpeas as well, so I think it would be OK to her.
I do not plan to eliminate cereal 100% from her diet but just to invert the ratios with legumes (it has been 4:1 so far), and focus on rice and corn for ceral meals rather than choosing wheat and other glutenous cereal.
I would like to know opinions about this idea I just came upon , if it can be safely done or if it is unwise in any way to feed legumes to a baby as a staple food.
I also would like to know whether green peas fit the legumes category or the vegetable category.

many thanks