It looks like you've already got a list of things you want to answer in the meeting, so you've already done the most important preparation.

I'm unsure as to whether this conversation will be private (me talking to a DSB representative), or if one of my parents will sit in.

This is probably under your control. I expect you have the right to a private meeting, if you ask the DSB rep. If you're worried about how your parents would react to such a request, maybe try framing it as practicing your independence, or something appropriately harmless and fuzzy-sounding?