First of all it's good to see that you are buying btc because many people out there don't realize how good a thing bitcoin is and they ignore all the advice bit coiners give them, and look at the price now, they've just missed out on the chance to make over 500% of their investment over less than one year.
You should always look out for scams out here especially when trading P2P.
Exchanges i recommend would be Coinbase, wesellcrypto if you just want to get your hands on a few dollars worth and don't want to verify yourself when just buying $10, virwox(high fees but no verification and higher limits than wesellcrypto), and localbitcoins.