Just wanted some insight as to why this girl did this to me lol

I dated her for a couple months about a year ago. Once I asked her to make it official she said yes, then said she wasn’t ready for a relationship, then changed her mind, then ghosted me

Haven’t talked to her in a year

Yesterday she messages me on Snapchat about my story of a new puppy I adopted asking if it was mine (even tho shes already viewed multiple other stories I posted of the dog previously), then once I asked how she was doing and stuff she just stopped responding again

Is there a reason someone would not talk to you for a year, then message you briefly just to ghost you again? Lol

Thanks for any insight