I have a question

Re
I'm 6 weeks pregnant and I plan on volunteering at an animal shelter starting tomorrow. My mom mentioned something about I should be careful because the animals might have diseases that might harm the baby.. Well now it's worrying me.. Should I still volunteer or no? I have two cats at home, but they are both inside cats.. So I'm not to worried about the cat litter.. Should I be? Please respond if you can..