Congratulations!
She'll keep laying for a while, but not forever. Usually they only lay in spring, but some may go through a second laying in fall.
My goose started laying in October when she was six months old and laid 44 eggs before stopping. I think she's about to start again soon; she's getting interested in hay and nesting areas again.
She's my only goose and the eggs are not fertilized, so there's no idea in her sitting on them. Most geese lay 6-20 eggs before sitting, but some decide three eggs are enough and start sitting on them.
If you want her to hatch out goslings, you can take away her eggs until you have the desired amount. Let her continue laying until she starts sitting and then give the rest of the eggs back to her. Geese can't really count, so she'll not wonder where the eggs went in the meantime or how they suddenly turned back up. Let her keep one (marked) egg - or a golf ball - in her nest, otherwise she may start a new nest in a different location. Just keep in mind that there's a limit on how many eggs she can effectively sit on. 15-20 is usually the maximum.
Young geese may need a trial season to fully master mating, fertilizing, nestbuilding, and sitting, so don't despair if it doesn't work out this year. They'll be much better at it next year.