I need help deciding between a new job and my previous job. What should I do?

Hi. I had been working at my previous company for 5 years. My sister in law’s mom, who owns a business, offered me a job at her company. I wasn’t ready to switch jobs but they were very persistent on wanting me to work there.

Long story short, I left my previous job and took this job offer for a better salary but so far I’m not too happy. I’ve already worked there for 3 weeks and I don’t feel like I’m being trained properly and my tasks are a lot harder than I expected. I feel intimidated by the person who’s training me because she doesn’t seem too nice and I already have a feeling I will not get along with her. She’s the type of person who wants you to learn quickly with zero mistakes. And they had promised to take good care of me and offer training.

I reached out to my previous boss to see if they had found a replacement yet. She said no, so I asked her if I could come back and she said she would get back to me this week (this was on Friday).

But now I feel like I gave up too easily and I should’ve talked to these people first and expressed that I need better training. What should I do— I asked my mom for advice and she said to talk to the people at this job first and if if my previous manager takes me back to tell her that I want to try out if things get better at the job to give her a final decision. But I don’t know if this will make me look bad, like I’m giving her false hopes and I’m not being serious. But my mom says it will look bad if I leave this job without having a talking with them and expressing my concerns since it’s a family business. They will probably be offended if I leave too soon.

What do you think I should do?