my dog is aggressive towards small dogs and it makes it hard to take her out on walks

my 10 year old dog is very aggressive towards smaller dogs and animals and idk what to do. Last year, she bit my aunts little dog and she killed a cat when she got loose.

When I try to take her on walks, there are a lot of dogs in my area and she pulls barks and snarls at them. she does this to big dogs too but she wont bite them. But this makes it pretty impossible to take her out on walks and my mom wont get her a trainer so im kind of lost on what to do.

any advice

ps. sorry if this is the wrong subreddit please redirect me to another if this isnt where i should post this