From the examples I've recorded, yours seems about typical size/weight for the type.
Maxentius seems to have issued two denominations of fractions.
The VOT X FEL type measures around 19-20mm and weighs ~2.7g
The VICTORIA AETERNA AVG N (VOT X) fraction seems to be same denomination as VOT X FEL, although I've seen a few heavy outliers at 3.29g, 3.66g, 3.86g. I assume that as usual it's the die size that is being controlled and the flan size and weight are not really very good diagnostics.
The VOT QQ MVL X & XX types are clearly a smaller fraction and seem to average around 17mm with weights in 1.7-2.2g range.
I'm not totally clear what fraction of a nummus these two denominations represent, maybe 1/2 and 1/3 (although many nummi seems to be well above the implied weight standard). The above sizes and weights are from actual specimens.