Have you looked through the
Health and Safety and the
FAQ sections of the forum? There is a lot of information to be absorbed there and is a great place to start.
No one can tell you what to do. There are plenty of people who jumped headfirst into DMT as their first psychedelic experience and they came back just fine. The key is to start with smaller amounts and build your way up in dosages. Ease your way in, there is no rush...the experience isn't going anywhere. However, the difference in intensity between properly vaping 20mg and properly vaping 30mg are pretty vast, so that is something to keep in mind as well.
Also, I would highly recommend look into getting a better device to ingest it with. Oil burners are not ideal and tend to burn the DMT, which destroys it. Search the forum for other methods such as DMT sandwiched between herbs in a bong/bowl, enhanced leaf, changa, GVG, VG, etc etc to learn more. If you only have a minimal amount of DMT to work with it would be wise to invest in a proper route of administration.
What to expect from the experience? In my opinion, try to leave expectations at the door. Once you take a toke, intentions and expectations are left behind anyways (in my experience) to make way for the impossible. It is a powerful, mind altering tool. Approach with respect and caution and you will be okay.
Good luck and welcome to the Nexus!
Edit:
Why you should NOT take DMT
This thread is a good read for all people about to take their first plunge.