Terrified to have a child with disabilities...

I apologize if this seems tone deaf. I don't mean to be. I have friends with children with autism and they tell me how difficult it is. My sibling is also on the spectrum. I really want to have kids and I just want to have normal and healthy babies.

I am currently limiting vaping and will taper off completely. I am taking nicotine gum. I have a sibling who is autistic.

I am 24. I am scared my nicotine use (for about 2 years now) and the fact I have a sibling with autism will increase my chances.

Is there any testing I could do, or am I much more likely to have a kid with autism? How can I reduce my chances?