Is it ok to have the same car as your sibling?

The car is a Toyota Passo, fits my budget, odometer requirements and year type.
Car im looking at has:
Reverse camera 
Screen
Pale yellow interior 
VS
Sister:
No camera only stereo
Black interior 
Both are black as well.
Bur my mum said if it was a different colour it would be ok, which doesnt make sense cos the interior is completely different.
What do you think? 
Is it ok to have the same car and colour but different interior?
Thanks!
Tha

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