I have been out with this girl 6x's already. I text her on a Wednesday to make plans for Saturday. She enthusiastically responded with exclamation points, emojis, and how that 'sounds fun'. I set things for Saturday, she said she can make it (though I didnt give a specific time yet) and she continued the conversations asking me about things giving

emojis etc. All seemed good.
There is no contact between us until I message her early Saturday letting her know what time I can pick her up that night. She replied "ugh I totally forgot

" and then "im sorry' nothing else. I replied "its ok no worries" (trying not make a big deal out of it) and nothing else from her. No suggestion for rescheduling, or saying some other time, or asking when Im free. No signs she wanted to converse or see me after 'forgetting'. There was no contact either way for a week after this until I text her a pic today that was an inside joke between us to test the waters. Her response "aww thats great haha!". Her reply didnt suggest she wanted to engage in convo so I didnt reply.
So it appears her interest is dropping. But I'm confused why when we're dating, things are going well, and she eagerly accepts the next date she all of a sudden 'forgets' our date and goes cold. Should I actually believe she forgot? (she is busy starting a brands new full time job beginning September and takes classes 3 nights a week also so shes a lot busier now then when we started dating in the summer). Regardless if you are truly feeling someone you don't 'forget' when you can see them again. Is she just too busy with other things in life that dating isnt a priority now? I plan to leave things alone and not message her until she reaches out to me. Any other insight or advice how to proceed would be appreciated. Thanks guys.