Yes, the system is still in an armed state. You will be notified before emergency services are contacted. If its in the normal timeframe for your daughter to get home you can cancel the alarm.
Also, you can provide your daughter with her own passcode to the security system. It allows multiple users and you can even set which days its valid on. You can do that from: https://www.xfinityhomesecurity.com/sp/keypadaccesspage.html
Chris