your body is adjusting so i wouldnt worry about your supply. if she were to need more, she should be able to get it. as for starting milk, if you want to continue nursing, you can. just because she is one, doesnt mean she has to stop. breastmilk is more nutritious than anything else.
for your question, i think she is eating alot if im understanding it right? in general, breakfast varies with cereal and such and breastmilk is included either before or after. then i feed 2 jars or equivalent per meal, usually nursing a little while later where the nursing is the mid morning or mid afternoon snack along with some puff or cheerios. then after dinner before bed is nursing. your baby might have a big appetite, but i think she isnt nursing as much since she is eating alot. although 3 jars is def on the higher end, it might be what she needs, but i dont think the before bed is needed. its a 4th meal that should probaly be another nursing session somewhere in the day.
no matter what you do at one- milk or continue nursing- she should do fine without that meal. i would offer her to nurse before the meals, so for dinner, nurse first then feed food. then another nursing session at bedtime and you have replaced the calories from that 4th meal. always remember, the first year, breastmilk should be the main food with solids complimenting it to help assist in getting ready for table food. after the first year, the solids become the main source with the nursing complimenting them. the amount of food may also be related to her constipation. good luck