A method for performing wireless communication by a first device and a device for supporting same are provided. The method may comprise: receiving, from a second device, first sidelink control information (SCI) including one field related to a sidelink (SL) channel state information (CSI) request; receiving, from the second device, a SL CSI-reference signal (RS); obtaining a SL CSI report based on the SL CSI-RS; transmitting, to the second device through a physical sidelink control channel (PSCCH), second SCI for scheduling a physical sidelink shared channel (PSSCH), wherein the second SCI includes priority information; and transmitting, to the second device through the PSSCH, the SL CSI report.