She will not be charged for burglary, since it is clear under the circumstances that she did not enter the house for the purpose of stealing or injuring the person of another. She entered the house to smoke with her friends, and the Contra Costa District Attorney will likely treat this case with an eye toward reforming the minor's behavior regarding drugs.
Possession of marijuana more than one ounce is a misdemeanor with a six month maximum plus a fine, there is no crime for being under the influence of marijuana only. I cannot guarantee you that she will not be charged with burglary, and a residential burglary is a potentially serious felony carrying up to a maximum of 6 years in custody. Alternatively, this could be a simple trespass. Consult with an attorney immediately because given her age and lack of record she needs a good advocate to attempt to minimize the impact of this case on her future. good luck.
each case is different and is based on the facts and circumstances of the case, the parties involved, prior record, aggravating and mitigating factors, skill of the attorney, etc. Hire a local lawyer ASAP. Good luck.