For me, the advantages outweigh the disadvantages. Determine what's most important to you. Trading for a career is a lifestyle change. Depending on which instrument you trade, trading can be done on your schedule. I trade equities between 9:30-12:00 am. EST. take the rest of the time setting up my trades and evaluating past trades.
Most important, Make a Trading Plan. You wouldn't start a business without a business plan, the same with trading. Be specific! What instruments will you trade? Pick 4-5 and get to know them and their characteristics. Under what conditions would you enter a trade & when would you exit. Are you intraday or swing,or both? What is your risk to reward ratio? Base this on your tolerance for risk. Be diligent is setting your stops and stick to them. Don't add to losers, get out, there is always another trade. Let your winners run with trailing stops. Be disciplined enough to STICK to YOUR RULES. Emotions will make you go bankrupt. The trick is to manage your losses. Focus on not losing (controlling) and the profits will come. Accept the fact that you will have losses, everyone does. Distinguish the difference between trader and investor. Warren Buffet is an investor, he buys and holds. Traders flip stocks (long or short) within minutes (scalping), longer intraday (momentum), or overnight up to several weeks (swing). Decide which you are, or what combination. FOLLOW YOUR RULES!!!
Find a good trading platform. I've used a few and currently use TradeStation. This is not and endorsement. It works for me, maybe not you. It's strong on equities, not so much on other instruments. Just a personal opinion that fits my style.
If your going to do this for a living, INCORPORATE. An LLC is fine, you may use it with a "C", check with your accountant. Make sure your accountant is familiar with pattern day traders accounting rules otherwise it could cost you. Two that come to mind are Green Trader accounting (Green is the accountants name) and Traders Accounting, both have websites. I use neither, my CPA is familiar with the rules.
Last bit on advice is to paper trade first. Use your plan to be sure it works. Make adjustments as necessary. When you go live begin with small share size (50-100). If your profitable, gradually increase. Depending on your commitment, it could take you a year to become profitable. BE DISCIPLINED, or you will fail and blow your account.
SEC rules require you to have a $25,000 account to day trade equities (4+ trades within 5 days), futures (emini's) can be traded with less investment and can be traded around the clock.
ONLY TRADE WITH WHAT YOU CAN AFFORD TO LOSE. Scared money never wins.