how am i supposed to feel like i know who i am?

i'm very new here, so if i break any rules i apologize. the hardest part for me with my bpd is feeling so disconnected from my personal sense of self. it's like i know that i'm a complex person with preferences and opinions and a variety of interests, but i feel so far away from what those interests are.

growing up i spent a lot of my time hiding in my room and focusing my energy into who i felt like i was and wanted to be as a person. it's like i used to have a bunch of qualities to my personality, but the less i've focused on keeping all the pieces nicely stacked together, the further they've scattered and now i'm aware that somewhere out there is my taste in music and my favorite color and ideas of what i want my wardrobe to look like, but they feel lost to me and i don't know how to get them back.

i'm really into planning things, i plan everything to the tiniest detail, even though few of my plans are ever seen all the way through. i've tried creating large inspirational collage boards, identifying things that i like and find enjoyment in and plastering them all together on a poster board, but it seems so surface level every time i do it, no matter the depth of thought that went into the board, but i wish i had a visual aid to remind myself of the person i'm trying to be.

i think i'm supposed to ask a more direct question, i'm not really sure what i expect anyone to say about all of this, but general advice would be greatly appreciated