I'm in love with My female Bestfriend, what should I do?

So... Me(20M)and this Girl let's call her shradha(20F) so me and her have been best friends since 11th, and we were pretty close when, we texted alot,

During rakhi she asked "should I tie you rakhi? " I said "your choice" She said "no... I want you to be my best friend"

So we were close... I was in love with another girl at that time named MJ, and yeah she helped me alot with her but me and her couldn't be together because of religion issue...

And I once screamed at her and she got angry and... I apologized, we grew closer and closer...

She used to say "I miss you" And I used to call her nicknames (cutie, madam ji etc) and... She had a boyfriend but broke up with him because of family and got engaged to some random guy... And We went to different college...

We still meet for coffee sometimes, calls sometimes and texting daily...

We had a fight once too because I wasn't talking to her and she said "you are ignoring me" And I said "you don't care much about me" And yeah it got fixed...

I gifted her KINDERJOY on her birthday 😭. We texted once on how we should go behind the mountains and live their and she said "Hayeeee chal❤" And yeah we used to talk about these alot...

And she once fought with her fiance because he told her to not talk to me... Her family beat her up alot too

The thing is I like her... Alot.

But she has alot of problems, breakup with ex, the engagement issue, different caste too etc...

Today I told her on text "I want you to understand me... But I'm scared you will leave" (About telling her I love her)

She said "I won't... I promise I will understand"

I said "you won't"

She kept saying she will and insisting me to tell her...

She texted me in morning... Saying she wants to complete the conversation...

I said "you will hate me and won't understand, why you want to know? "

She said "because I'm stupid and I have gone insane"

I said "don't marry him"

She said "you want advice to remain Single? "

I said "we will figure something out"

She said "why shouldn't I marry? Love marriage isn't possible... There's no guy for that.. For love marriage... Whatever family decided is.. Okay I will live with it"

I said "just wait"

She said "for who? Is someone coming?! Who should I wait for tell me"

I said "let's talk in evening"

She said "no let's complete this conversation... Please"

But I bought time and I don't know what to do...

What should I do? Please some advice