I'm biased, but I completely think an agent is necessary. Even if you compile some comps, it really takes a good agent to both evaluate the comps and calculate necessary adjustments. A good agent will then use that CMA to negotiate with the seller's agent. An agent can also make appointments and show you several houses in a day. If you go it alone you'll have to contact each listing agent, and believe it or not, some listing agents will not come out to show a property. I know people argue you can get a better price without an agent, but I disagree. Not only do you save money by having a professional price opinion that an agent can use to negotiate the best price, but the seller has already agreed to the commission paid to the listing agent. Even if a listing agent says they'll reduce their commission, their broker will have to approve it. And a lot of listing agents won't do it because it results in more work for them.
Also, don't use "zestimates" for your comps. They're rarely accurate.
A lot has changed on the Tennessee Association of Realtors purchase contract. It's important to have an agent walk you through it all, otherwise you can forfeit your inspection rights without even realizing it. And this can happen to the most intelligent person out there. I'm in no way saying you're incapable, but a home is the biggest purchase in almost anyone's life. Wouldn't you want a professional to make sure everything from offer negotiation, inspection and other contingency removals proceed to a smooth closing? Even attorneys use real estate agents (unless they practice real estate law

to save them not only time and energy but any potential problems down the road.