If you want to know for sure how good your chainline is then get a (good) vernier caliper and measure it.
A=width of seat tube
B=width of chainring
C=distance from far side of seat tube to outside of chainring
D=width of hub (outside flange to outside flange)
E=width of cog
F=distance from outside (driveside) flange to inside of cog
C-((A+B)/2)=F+((D+E)/2)? If so, perfect chainline. If it's off by a mm or less, it's close enough.