TOPIC: "Keep in mind"

I look up the dictionary I found that "keep in mind" is a fixed structure or idiom. But I heard someone say, I keep it in MY mind. So, I was wondering which of the two sentences above is better or right.

Thanks for your help

"Keep something in mind" is a fixed structure or idiom meaning to remember something when you are considering or making a decision. We also say" bear in mind" with the same meaning. It CANNOT be changed by the addition of " my/his/our etc. mind"
But then if you want to say you're having trouble remmbering something, i.e. you keep forgetting it , you could say " I just can't keep it in MY mind", or if you're talking specifically about trying to remember, you might say, " This is very important; I want to keep it in MY mind forever.

Here 's the example
"Bearing in mind how young she is, I though she did really well.
Of course , repair work is expensive and you have to keep that in mind."
Note how the "bear/keep in mind" part in these examples is not used as the main verb. But we could also say,
"Keep in mind that he is very young so you can't expect his performance to be perfect."