The Commonwealth of Pennsylvania has set a minimum gambling age of 18 for most forms of gambling but 21 for casinos and poker rooms. These same rules transfer over online, so you ought to be 21 to be in full compliance with Pennsylvania law when you log on for a session of online poker. However, the poker sites aren't realistically able to keep abreast of age of majority rules in thousands of jurisdictions around the world, so they'll allow you to sign up and play as long as you're over 18. It's up to you to ensure you're following the rules. If you're under 18, we advise you not to open an account at any online gaming site because you might have trouble with identity verification documents when you attempt to withdraw your winnings.