I think as long as you (register with the admissions office- your intent to take a certain number of units) and then take them you will be ok. 12 units is 12 units anyway you slice it. If this is the case what can your insurance say? Unless there's an exclusion or a rider (seriously doubt) that says you have to be at a traditional school enrolled in traditional classes this doesn't apply? Most schools just say enrolled or "attempt" 9-12 units.

Otherwise... unless you need $500 a month insurance you can get decent insurance for about $100- especially at your age.

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The best things in life aren't things.
~Brandon