I got a new job dilemma

Hey everyone,

So a little back story I already have a full time job which is alright, but I was trying to get into a career of what I went to school for.

I looked for a position for years and finally I found it and applied, they called me back after 3 days.

I went in for an interview and 2 days later they called me back and offered me the position.

Here's where my dilemma starts, I cannot afford to give up my fulltime job at the moment because my career position Is only part time opposite to my full time which works for the most part to work both jobs.

My career position also needs me to come in for training paid for a whole week During the times I work full time.

I'm not sure what to tell my full time job in order to book it off with out them getting upset I just came back from maternity back in Dec. So I feel like they will be mad..

Can anyone please help me? I'm really feeling anxious about the whole thing.