What’s a jailbreak?
A jailbreak is simply the ability to run apps and use themes and tweaks not approved by Apple. Jailbreaking doesn’t slow down your device or use any extra battery. A jailbreak lets your device be how you want it. 
How can I be sure I always can jailbreak in the future?
Most importantly, allow Cydia to “make your life easier”. This will allow you to always restore back to the latest firmware available when you select that option. (Plus it actually increases the phones value if you ever want to sell it to someone.)
1.Is jailbreaking reversible?
Of course! If you ever decide that you want to remove your jailbreak, just connect your device to your computer, sync, and then press Restore in iTunes.
2.Is this legal in the US?
Yes. A new DMCA exemption was approved by the Library of Congress, specifically allowing jailbreaking.
