Yes, that's very possible, in fact, rather realistic. 
An interesting fact to remember when you're wondering about how long a memory can last is that you can blind fold a person and then take them into a room with a crowd of people, take off the blind fold for a second (or a twentieth of a second... I think, not sure), blind fold them again, and take them out. Then never have them see the room again. And twenty years later the image of the room and faces of each person will still be in that person's memory, just perhaps not readily accessible. 
This means that it's not really possible to entirely forget something, especially your entire life and special events in it. Which means her memories will probably still be ingrained in her subconscious and they come out sometimes (such as, like I said, in irrational fears, nightmares, and such, even sometimes headaches during certain situations, if she has head trauma). 
Therefore, she would probably have dreams (or more likely, nightmares) of things she can't exactly remember. Odds are though, the dreams would be foggy and sort of hard to follow. On a rare occasion, a dream might reveal an entire memory, but I would think something would have to trigger that such as an event that came to pass that day or something she was thinking about as she fell asleep. 
Also, memories could come in more than dreams. She could remember something while she is awake, perhaps not an entire memory, but a tid bit. 
NOTE: If she remembers something traumatic she will probably suffer from physical symptoms too. Such as shaking, sweating, stuttering, light headedness, it's possible she could pass out too, if she forces herself to think or say the memory aloud. 
And a final thing (I'll stop ranting after this, promise 

) is smell. Scents are even more easy to remember than sight. Why? I don't know, but they are. Your mind will never forget a smell. Which makes them excellent triggers for supressed memories.
Bethany Faith