I buy some items online, but then again I've been a bicycle mechanic since age 14, now almost 33. Wow, more than half my life. That's a wierd revelation.
Anyways, since you mentioned being new to cycling, I would advise against purchasing online. Go to ALL the shops in your area, introduce yourself and explain what type of riding you're planning on doing. Believe me, they're used to people in your exact situation and will be amicable to your apprehension. You'll probably find a great shop that you like, or one that rubs you the wrong way. Eventually, find one where you feel comfortable spending your money and makes you feel like they care about you and your needs. Spend your money there! They'll help you get the right bike in the right size for the right money!
Shopping online can be catastrophic if you're new to the sport, you could end up with the wrong size bike or the wrong bike for your needs or a piece of overpriced junk. Plus, when you get it shipped, you have to assemble it. This requires some special tools which you may or may not have. Also, in order for everything to work right it has to be tuned properly. This requires some bicycle mechanical knowledge which you again may or may not possess.
Plus if you deal with a LBS, you can get local knowledge about where to ride and perhaps a group ride to get to know other people in your area.
L8R
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"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming, "WOW, What a Ride!" - unknown
"Your Bike Sucks" - Sky Yaeger