Is it illegal for a 14 year old to talk sexually to another 14 year old (or maybe younger) in chat rooms?

Both 14 year olds are in violation of California Penal Code Section 288.2 INTERNET SEX WITH MINOR and CALIFORNIA PENAL CODE SECTION 647.6 CHILD Molestation. 288.2. (a) (1) Every person who, with knowledge that a person is a minor, or who fails to exercise reasonable care in ascertaining the true age of a minor, knowingly distributes, sends, causes to be sent, exhibits, or offers to distribute or exhibit by any means, including, but not limited to, live or recorded telephone messages, any harmful matter, as defined in Section 313, to a minor with the intent of arousing, appealing to, or gratifying the lust or passions or sexual desires of that person or of a minor, and with the intent or for the purpose of seducing a minor, is guilty of a public offense and shall be punished by imprisonment in the state prison or in a county jail. PC 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.

There are many crimes involving enticing a minor. Do not use chat rooms. Meet real women in real life and make sure they are 17 or it is a crime to do or say anything sexual. Also, half of them are cops.

Whether it is illegal would depend on many facts not included in your question, including the exact nature of the conversations. As a 14 year old, it is possible that you could be classified delinquent by a juvenile court. Much more important, in my opinion, than whether it is legal is the fact that it is extremely unwise. Adult predators often use such chat rooms to stalk minors (both male and female), befriending them and often arranging to meet in person. There are too many instances to count of minors being sexually abused, or worse, because of this. It is often easy to think you are anonymous in such rooms, but there are ways to trace people through IP addresses or other means. The bottom line is the activity may not be illegal, but it is extremely dangerous. Victims of the predators often do not learn this until it is too late.

Perhaps, but in any case it is VERY foolish.