Join Date: Jul 2013
Location: Tehachapi Mountains, CA
Really, you can do what you like. Neither option is wrong, but, as others say, is horse dependent and rider-skill dependent. If it gets to a point you feel it is moving too fast for horse or rider (or both) you can dial it down. But you can just not ride, too. Your choice.
If it were me, for this partiuclar horse with the description given, I would ride the first day. But not much. I'd spend time getting her ready - really do a nice slow grooming session so she feels good & relaxed. Get on and see what she knows - but go slow and easy so she does not get out of the relaxed state, lots of stops and sitting and petting; maybe do about 15-30 minutes of slow work and see what her gaits are. Then I'd do a long slow cool down/grooming session and put her up with a snack. Make the entire experience something she'd look forward to.