Yeah it looks OK. The concentration is good as well, I quite often mesaured samples with as low concentration as 1,2 mg/mL (0,012g/mL) and it went well.
There are multiple ways how to confirm your measurement, for example, you can do the same sample in tube that is 10cm. Or you can dilute the sample and measure it again. If your meassurement is correct, then you should get the same value in the end no matter the sample concentratio and path lenght.
You can also compare with literature values as suggested by AWK (if they are known). FUrthermore, if you measured both eantiomers, then you should get the same value with opposite signs