1996.... damn I feel old.

First question to ask is what airline has bases where you live.
Second is how long it takes to get said base.
Third is what type of planes they fly
Fourth is how long to upgrade
Fifth is how is their pay and how long will you reserved
Sixth is how is the company doing and do people like the company
Seventh is how many flying hours you getting a month, and how long till you can leave to go to a real airline...
Etc

All these questions and more are to be asked and the order of importance is up to you....

No it's not, it's expected that you probably would unless the place you're interviewing is the only place you want to go to for whatever reason and even then I would explore other interviews to get some prep in, who knows you might even be open to a new place then.

The absolute key thing is that if you take a job somewhere else and you have CJO that you contact the companies you aren't going with and let them know, don't burn a bridge.

I cannot emphasize enough how small this industry is. Everyone knows everyone, everyone knows each other's stories, if not directly, through your co-workers. Don't be a dick to people, don't trash talk others, always leave on good terms, and act honorable.

Isn't being 23 years old a requirement?

21 for a restricted ATP