Lithuania is a country in the european union. hence routers sold in Lithuania have to abide by the EIRP limits.
the EIRP limits for 2.4ghz routers is set to max 20dbm.
so your max power of 17dbm + the 3dbi antenna gain should give you the 20dbm total effective irradiated power.
so no issues for you since 17dbm will be the max your allowed and the router is restricted to it.