Don't worry that's a good mark!
I got about 110 in the first practice test and I ended up getting 98th percentile in the actual UMAT. I've heard people say the ACER test is significantly easier but I honestly didn't think so.
Either way I'd say it's almost impossible to extrapolate what you will get in the actual UMAT based on raw marks in practice exams, so don't give yourself more stress about the exam.