are there any bumps at all on its face? and a female BN, correct me if im wrong experts getting mine next week, would be full grown at five inches and would noticeable bristle by that time. So thefishboss is almost definitely correct with a common pleco.
Also besides the size and lack of bristles... BN plecos have a flatter head, yours have a very blocky head like a common pleco.
"In comparison with a typical
pleco, a bristlenose is typically shorter (15 cm or less), more flattened and fatter with a comparatively wider head."
-simple search provided this