Hi AParent. Welcome to BleepingComputer :-)
You can create a limited account for your teenager kids. They wont be able to change any system settings that way. The Network Connections settings are greyed out (disabled) in such an account. To create a limited account. Goto Control Panel > User Accounts
and click on Create a new account
when asked choose Limited Account
Besides as a parent concerned about kids, you should use FREE OpenDNS' DNS servers ( http://www.opendns.com
). You need to register at their site and choose options what kind of sites you want to filter (like porn, drugs, hatred etc). Then download their client and install it. More information at their site.