Managed to land a junior role need help!

I have only been self taught for the past 6 months and have only been programming solely with C. I have been fortunate enough to have been offered a position with a company as a Junior Software Developer after passing the interview, I've informed my employers that I am severely inexperience and they understand (i hope so).
My employers are assigning me a mentor and willing to give me up to 3 months to get comfortable and productive with rust. I've done my research with the book, rustlings and a few youtube videos.

I am starting this 19th and was hoping to get some advice on how to jumpstart my transition to rust from (very simple) C, and a question,
Whats a acceptable amount of time that it would take for someone coming from a background in C to be able to pick up rust and be production productive?

Coming from an entirely procedural POV i have very little knowledge in OOP and FP concepts how much will this affect me and is taking the time to explore the concepts further needed in the future ?
Thank you fellow rustaceans!

EDIT: added question regarding paradigm knowledge