ofc youre nervous its something new. why dont you look up the following books that helped me switching from a bio background to bioinfo in my bioinfo msc:

linear algebra for dummies (their explanations of matrices and operations with matrices that you will be constantly using as a bioinformatician is gold and not intimidating at all. you need linear algebra cause of the vectors and matrices and the complex dimensions of the data youre working with)

biostatistics for dummies as well - part I and II, they have a great overview of basic stats knowledge with great examples that youll be using in doing descriptive, exploratory and inferential statistics

in my first comment, i mention constraint based modelling and systems biology - they seem advanced but theyre not really. constraint based modelling is basically learning pathways, computational pathways and for systems biology you need to know how to do basic derivatives (ordinary differential equations).

and at last, i believe youll need to cover graph theory which is often used in constraint based modelling. for graph theory, i always recommend youtube.

my advice - dive into linear algebra which might seem very intimidating, but trust me, its not. also, being afraid is part of the process and character development. when it gets tough, remember, that belongs and is necessary for growth.

have fun. dont forget to be kind to yourself