Short answer. You may appeal right away. The rule lists an order or judgment that allows or disallows a will first among those an interested person may appeal in special proceedings, so it does not have to wait for the settlement to be completed.
What the law says
An interested person may appeal in special proceedings from an order or judgment rendered by a Court of First Instance or a Juvenile and Domestic Relations Court, where such order or judgment: (a) Allows or disallows a will
Rule 109, Section 1 — Orders or judgments from which appeals may be taken. Read the full provision →
It heads the list for a reason
Whether a will stands is the question everything else in the proceeding depends on. If it is disallowed, the estate is distributed on a footing entirely different from the one the will set out — different recipients, different shares, sometimes a different person administering. Making that order appealable when it is made, rather than at the end, means the foundation can be tested before the whole administration is built on it.
The provision cuts both ways
The clause covers an order that allows or disallows a will. It is not written for the disappointed beneficiary alone. A person who contested a will and lost — where the court allowed it — is within the same listed ground as one whose will was struck down. The rule is concerned with the type of determination made, not with which side it went against, and the right belongs to any interested person.
Understand what is being appealed
It helps to be precise about the order in your hands. Disallowance is a ruling on the will as an instrument. It is a distinct thing from an order determining who the lawful heirs are, or one fixing a distributive share, though the rule makes those separately appealable too and in practice they may follow closely from each other. Identify which determination the court actually made, because that shapes what the appeal is about.
Do not let the period run while deciding
Because this order is appealable now rather than later, the time to act is measured from it. Note that the same rule expressly withholds an appeal in one situation — from the appointment of a special administrator — so the fact that the proceeding is ongoing does not mean every order in it can be brought up. The rule also excepts an order granting or denying a motion for new trial or reconsideration from the final-judgment ground, which is a further reminder that the list is specific rather than general. Take the order, and the date notice of it was received, to a lawyer without waiting to see how the rest of the settlement unfolds.