The thought of eternal Jannah or Jahannam makes me feel anxious

I've been thinking about how after we die, it's either the fire or the garden for eternity – like, more than trillions of years, and it just never ends. My mom, she doesn’t pray much, only fasts and prays in Ramadan, but she’s not really into sinning, you know? She says she's too tired from all the housework and feels lazy to pray. I'm scared because what if I end up in Jannah forever and feel overwhelmed?