"means a lot for me" is correct and usable in written English. You can use it when you are expressing that something has a significant value to you. For example: "Having you as a friend means a lot for me.".
It means a lot for me and my family".
This means a lot for me at the moment".
"It means a lot for me have this trophy with me today.
"It means a lot for me to play for one team throughout my career and moving past such a legend as Alex Delvecchio," Lidstrom said.
It meant a lot for me in my career".
"It meant a lot for me to see the guy from the DOJ when he came and sat down with me, took down my information and attended several forums.
It really meant a lot for me to see Kwam, a successful, educated African American man with a family, willing to fly, take the train, or drive all the way to New York.
Since I tried Ludwig back in 2017, I have been constantly using it in both editing and translation. Ever since, I suggest it to my translators at ProSciEditing.
Justyna Jupowicz-Kozak
CEO of Professional Science Editing for Scientists @ prosciediting.com