Toddler sat on our baby

Hey there ladies,

My 3 year old (just turned 3, she is 13kg) was walking backwards and the baby was laying on the floor when my 3year old tipped over and sat on our 3 month old baby’s stomach... the baby cried immediately but stopped quite fast after I picked her up, now she was acting normal and fell asleep (she always sleeps around this time a day..)

Has it happened to someone here? Should I be worried 😟?