Yes, honesty is always the best policy.
Gently let her know that your mates, their cars and going fast up some twisty bits are more important to you than some recent sentimental attachment for her getting older and meeting her friends & family.
Keep her keen and you should be right to go in no time!
However, unless you're back well before lunch/dinner, you may need to sew them back on before you go out again (& don't even think of trying to blame the car...).
Let's know how it works out.