No they have no real bearing, and the only real limits are those your mind places on you, or you place on yourself. She may be better attuned to her spirituality then you are thus why she is better able to remember. Also being three hours apart doesn't mean anything at all, that is more about distance then time, cause its all still in the same frame of time, just in a different location. Also as for her remembering better, for the most part your energy is flowing to her more than hers to you, basic male female interaction, specially being in an intimate setting.
For me, I never remember much of anything anyways, so not remembering the details of an encounter doesn't mean much to me. I'm also generally too focused on just making sure the connection stays strong and just lets my subconscious do all the work. And to a degree one part or another of my subconscious tends to always be projected out doing something or another. Its all about perception really.
As for trying to mess with events that have already happened or are supposed to happen, it could be painful trying to mess with them, and is advisable to avoid doing so.
I believe that there is a passage of something like time in the astral plane, but it doesn't act very much like time does in the regular world. It seems to move considerably slower, but if you spend enough "time" in the astral plane you will begin to sense that even there some "time" has passed. I haven't had much experience in manipulating the past or future when it comes to astral, but i would imagine that it's efficacy would be dependent on the strength of your will.