Baby Sleeves help!

I am making a baby sweater. When i got to the section for sleves i was rather suprised. If i am reading the directions correctly i think that the arms are going to be too long.

Cast on 39 Sts
knit/purl 14 rows adding 1 extra st. on the last row (40)
st.st 27 rows (adding sts to 54)

Continue without shaping until the work measures 5 inches from the commencement.

Does this mean from the commencement of the st. st without shaping? from the commencement of the st. st. with shaping? or from the commencement of the whole thing?

up to the 54 sts. is almost 4 1/2 inches. if the commencement is from the commencement oft he st.st. without shaping that would make the sleeve over 10" because there is another 38 rows of knitting after the st.st.

I know confusing but can someone help?

The length is the total length from the cast on.

thanks for your quick response!!!
That’s what i thought it was. although it seems i might have to redo the body part of the sweater!!
i thought that if the commencement was were the st st started it would be too long!!