Pgeary hi and welcome-
What is it that you are afraid of? Is it a fear of physical harm? Fear of the unknown? Fear of negative psychological effects? Fear of freaking out?
As others stated, it is completely normal to be nervous and have a healthy dose of "fear" going into this and as DeDao said, no reading or research will make much of a difference once you are in it. I read books, trolled the nexus for over a year and if anything it just made more nervous and "afraid" but once that vapor hit, it didn't matter... and by the time you pick your jaw up off the floor its over.
But as for practical advice (this is my experience):
Know and be confident that you WILL be just fine
Remember it only lasts a few minutes
Remember DMT has a long history (hundreds if not thousands of years) of use and is physiologically quite safe, it will be completely metabolized out of your body faster than shrooms take to kick in (this is regarding vaping spice)
As you go in and when you are in the trip, just keep telling yourself "I'm ok"
Take some time beforehand to read some inspirational trip reports
Be in a comfortable and familiar setting
Do all that you can to just let the experience unfold, fighting or resisting it is pointless and will only lead to panic.
Focus on the fact that this may be one of the most profound and thought provoking moments of your life, even if it is scary. That is OK and be ok with being scared, no big.
In my opinion, I wouldn't even mess around with a low dose, I find them to actually be more uncomfortable and less rewarding. A breakthrough wont leave you for much contemplation of any fear.
Ultimately, you know YOU best and know what you can handle and what it is you are looking for out of the experience.
I hope you have the solace you seek and know it's normal to be scared, in fact I'd say there would be something wrong if you weren't.
Breathe, clear your mind and just go for it.
You can't do anything about yesterday, but you can do everything with tomorrow.
Everything I write on this forum is pure gibberish and fanciful nonsense!