It’s possible that it may have reset her to the beginning of the toddler stage, you can check in her simology panel. Otherwise it’s harmless and you can just age her up to a child when you’re ready with a birthday cake.
From
Carl’s Sims4 Guide:
“
Its effects on living Sims are lackluster, given the Ambrosia Recipe requires the 1,500 Satisfaction Point Potion of Youth, which accomplishes the same as Ambrosia in bringing a Sim back to the beginning of their current life stage. To get a Ghost to eat Ambrosia, work on befriending them each time they visit then invite them to rejoin your Household. At that point, you have control and can bring the Sim back to life by ordering them to eat the Ambrosia. This is not, however, the only way to bring back the dead in The Sims 4. The Book of Life does the same, if you have a Ghost use the book once they're back in your Household.”