Like alcohol, anyone who wants to partake must be at least 21.
However, punishments for minors in possession of marijuana can be severe, with some even being charged with felonies (in rural Asotin County in 2015, but it's probably unlikely in most counties).
Historically, the age of consent applied to male-female relationships; same-sex relationships were often illegal regardless of the ages of participants.
Modern laws vary, and there may be multiple ages that apply in any jurisdiction.
Both partners must be of legal age to give consent, although exceptions to the age of consent law exist in some jurisdictions when the minor and his or her partner are within a certain number of years in age or when a minor is married to his/her partner.
Persons below the age of consent may not, by law, give consent, and sexual relations involving such persons may be punished by criminal sanctions similar to those for rape or sexual assault.
Non-violent sexual contact with persons under the age of consent may be punished with varying degrees of severity, ranging from a misdemeanor with a simple fine, to a felony with a punishment equivalent to rape.
The ages of consent in the countries of Central America range from 14 to 18.
These laws are situational and are subject to interpretation.