At what age is it okay for a minor to be with an adult?

Your boyfriend has set himself up for lifetime registration as a sex offender. You really should go ask your parents if it is okay for you to be sleeping with a 20 year old. It is such a reasonable question, I do not know why you haven't asked them to date. You must not have thought of that.

16

Sex with him will get him 15 years in prison. Of course it is illegal you are too young.

Regardless of the legality, I suspect that he wants more from you than to simply hang with you. As long as you are not having sexual relations or he is giving your drugs, alcohol, or tobacco, its not illegal. However, if you are engaging in any of the aforementioned (even with your consent), he can be charged criminally, and if convicted, he could go to jail or prison for a long time.

18

The laws governing the conduct between a minor and an adult are California Penal Code Section 261.5, Section 288 and Section 647.6. California Penal Code Section 261.5. (a) Unlawful sexual intercourse is an act of sexual intercourse accomplished with a person who is not the spouse of the perpetrator, if the person is a minor. For the purposes of this section, a "minor" is a person under the age of 18 years and an "adult" is a person who is at least 18 years of age. (c) Any person who engages in an act of unlawful sexual intercourse with a minor who is more than three years younger than the perpetrator is guilty of either a misdemeanor or a felony, and shall be punished by imprisonment in a county jail not exceeding one year, or by imprisonment pursuant to subdivision (h) of Section 1170.California Penal Code Section 288a. (a) Oral copulation is the act of copulating the mouth of one person with the sexual organ or anus of another person. (b) (1) Except as provided in Section 288, any person who participates in an act of oral copulation with another person who is under 18 years of age shall be punished by imprisonment in the state prison, or in a county jail for a period of not more than one year. California Penal Code Section 647.6 (a)(1)Every person who annoys or molests any child under 18 years of age shall be punished by a fine not exceeding five thousand dollars ($5,000), by imprisonment in a county jail not exceeding one year, or by both the fine and imprisonment.

I assume you're asking about sexual intercourse. In Alabama, if one party is 16 or older and the other party is less than 16 and the oldest is at least 2 years older than the youngest, the older party is guilty of 2nd degree rape, a Class B felony. This is commonly known as statutory rape, because the crime is defined by statute; consent doesn't matter. To answer your question, your situation is illegal - for your boyfriend, at least.