Welcome to BikeForums. If you can return the bike, ask the shop owner what hard-tail mountain bike s/he has in your size. If the shop has one you like swap the tires for slicks or semi-slicks and you're good to go.
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The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.