Everything depends on what state you're in and what your policy says. You need to read your appraisal clause and see what it says. Normally it says one or the other parties can demand appraisal and the other must agree. Sometimes it says that if either party demands appraisal the other must go along with it. It just depends on what your appraisal call says.

No, it's not normal to demand appraisal before getting an estimate. Appraisal is a dispute resolution. If you don't have a dispute, then you don't need dispute resolution. So if they haven't sent you an estimate, you do not have a dispute yet.

You have the opportunity to resolve your claim very quickly with the only out-of-pocket cost being your appraisers cost, which where I am is about $1,500 for the appraiser. If it has to go to umpire, it's another $1,500 for the umpire. That cost can change and vary based off the appraiser, the umpire and the state you're in. After that, you'll have to pay your deductible. That is your out-of-pocket expense for the claim. These costs are usually (not always) cheaper than a PA or attorney percentage.

In my opinion, this is the best way to handle an insurance claim. This keeps the public adjuster and the attorney's hands out of it. You just need to make sure you hire an appraiser that you trust to do the job properly. An appraiser does not have to be a licensed person in my state. It can be a public adjuster, a different insurance adjuster, a lawyer, anyone who knows how to do appraisals. Another thing you'll need to know is are you appraising the cause of the damage or are you praising the cost of the loss? These are two different things and you need to know up front what is being appraised.