Scared, no. Prepared and protected, yes.
Hundreds of thousands divorce every year and as I recall Bill Eddy, lecturer and author of our SPLITTING handbook, states in seminars that some 10% (plus or minus) can be high conflict. Courts know this happens, they still plod through all cases. What you need to do it for find a proactive lawyer and determine which strategies are best for your situation.
Custody and support issues are minimal. The children are with you and grown or nearly so. If she's been separated and away for a couple years, your history as primary parent makes that issue virtually moot.
Frankly, if there is a divorce, you would probably want it in your state since remote would probably be hard on you. (I guess you could ask your lawyer whether her state has more favorable policies regarding division of assets? But how you would make her file, IDK.)
If your incomes and retirement accounts are roughly similar then it ought to be a wash unless she fusses about the details. You both work and she's been living apart, presumably without your support, for two years so she not likely to have basis to request alimony. Hmm, maybe sooner is better, for this reason... .your daughter is still a minor, if you earn a little more than you spouse then you can always include your minor daughter as an expense and therefore reduce your income after expenses.
Strictly speaking, she is not owed half the house, she may be owed half the house
equity. Take the appraised price, subtract the mortgage and liens, and the result is the equity. Half of the equity might be hers, but best to get local legal advice. Have you consulted with a few lawyers? They're relatively inexpensive and you don't have to pay a retainer until you hire a lawyer you choose. It might be wise to have them review your paperwork to identify mistakes, too-timid statements or misunderstood instructions.
This is a new step for you, you're naturally nervous. But the first step is typically the hardest, the more steps you take on your chosen path the easier it will be.
Are one of you paying the other's health insurance? If so, then understand you can't drop the other during the divorce. Once it is final the insurances will require it, perhaps to choose COBRA if the person wishes, but
you can't dump not until the window period ends after the final decree.
If in USA, the good news is that once you have a Final Decree you can stop filing "Married, Filing Separately". Tax rates for "Head of Household" are slightly lower.
