And if Jackie is Jenny, she could clearly be referencing the prior interaction. And why wouldn't she remember? After all, MC looks exactly like he did decades ago because in his current reality he's only a few days older than he was in that interaction. While you may not have the faculties to remember things at 50-ish that happened when you were 20-ish, some of us have great recall when an event is something that was significant and/or with a person that was significant. When I see someone from my 20s that I haven't seen for 30 years, seeing them will unlock memories and events from that past. And keep in mind, if Jackie is Jenny, she's had years to come to the realization that MC is the same person she met before the accident, and is also realizing that he has hit that point in his life where his time travels are starting and their past interactions are real-time for him. Now would be the precise time to start dropping a subtle hint as to who she is here and there - she certainly isn't going to simply blurt it out without testing the waters to confirm he's in his time travel phase.
There is also "VN logic", which dictates that any coincidence really isn't a coincidence. This logic is present in books, TV and movies, as well. So, rather than being arrogantly dismissive, open your mind a little - let that
corpus callosum do what it was designed to do and let the logical side and the creative side talk to one another a little bit.
And, again - I don't know if this is what's going on or not, but in a
FUCKING TIME TRAVEL VN it isn't an unreasonable bit of speculation. What is unreasonable is being completely dismissive
(and increasingly dickish) without clear evidence to the contrary.