In the future Penny will marry an older version of Dash.
Penny has a special relationship with Bolt.
Penny received a name change at some point and was at one point an actual superhero named Veil.Seriously, Veil looks exactly like an older version of Penny.
Alternatively, she received a name change when younger and Penny's old name was Grace Goodwyn.As above, Grace looks like a younger version of Penny. Then again Penny Forester could be a fake name so it could be her actual name. It could go either way.