My hubby bought me a Trek almost 2 years ago for mother's day and I am in love with that bike! Like everyone else has said here, buying from a bike shop is smart move. They'll fit you to the correct size (I'm 5'9" and had to get a much bigger bike than I probably would have picked out on my own). Not to mention, most bike shops offer lifetime servicing/maintenance on the bike that you purchase.
My bike shop has been so good to me! I am slowly learning how to do minor repairs/adjustments own my own, but when it's out of my comfort zone, they are glad to do it for me.
A lot of bike shops even offer free lessons to show cyclists how to do the repairs themself - it's worth the 10-20 minute lesson if it saves you road time.
Good Luck with your new bike!!
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