Hi Max's Mommy, welcome to PT! did you post an introduction yet? I'll have to go check.

Terriers are, by definition, more prey driven than some other breeds. So you need to think about the breed generally, and the individual dog specifically. my next door neighbor has Bostons; no way they can be trusted with my cats. This is what happens:
- the dogs look at the cat
- the cat startles and runs (away)
- prey drive kicks in and the terriers begin the chase
- neighbor and I now join in, much further behind and losing ground all the way
- fortunately, both times, my cat ran into my garage and up under the car. We caught the dogs, took them back home, and the cat came down at her own time. Greasy and oily, but safe.

While it is POSSIBLE for a terrier and a cat to coexist, it does require diligence and training on your part, and a bit of luck as to the personality of the individual dog you get.