Thank you for this excelent explanation!!!In English, one way we frequently use the expression, Don't get ahead of yourself, is when explaining to someone that they are taking too many leaps in their thinking process. For example, persona 1 is relating to persona 2 how much she fears her child doing such and such a bad thing when she is a teenager, even though the child is only 7 years old. It's silly for her to be worrying or thinking about all that could possibly happen at this point in time.
This is just one example but the idea is that person has jumped too far ahead in his/her thoughts about a particular situation, problem, etc.