I agree. I mean right after that she expresses her fear that people wouldn't want to be around her anymore. She knows that once the fact that she's a sorceress got out, nothing would be the same and the only way to keep that safe moment between them would be to say that she wouldn't want time to go on.
She says nothing of the past though, because the past is okay, ironically, like D said TC would make the "past" AND the "future" irrelevent, since she just doesn't want the -future- I don't believe that supports R=U.
Not to mention, if Rinoa wanted time to stop because her love for squall, then why would her future self (ulti) try to not make it the same?
Rinoa's Goal would have been = To stay beside Squall in the most confortable of moments forever
Ulti's goal = To compress time so she could kill the ledgendary SeeD before they killed her in her future time. (Mind you, Squall could easily be this SeeD)
Either it didn't matter because the SeeD killed her and that took priority over her first want or because Rinoa's not Ulti in the first place.