Should I fill out a T2125 form for T4A line 048 when its for my 17 yr old daughter she is not self employed, just taught skating lessons?

Box 48 on the T4A is considered to be self-employment income by the CRA, so your daughter would have to fill out the T2125. She can put in her own name and address, and she can get an industry code from the NAICS website here: https://www23.statcan.gc.ca/imdb/p3VD.pl?Function=getVD&TVD=1369825