There are several plants with aureo marginata in their names. It literally means yellow margin. You will note that, properly written, the two words are together - Aureomarginata. So, not only does your plant not have a yellow margin, the title is completely incorrect as one might expect at box stores. Still, you've got a pretty little hosta there. I'd watch it to see what it grows up to be.
The following list from MyHostas.be
Fortunei Aureomarginata Nils Hylander/AHS 1987
Fortunei Stenantha Aureomarginata --->Brass Horn
kikutii 'Aureomarginata' Japan/Herb Benedict --->kikutii 'Kifukurin Hyuga'
kiyosumiensis 'Aureomarginata' Japan --->Kifukurin Kiyosumi
montana 'Aureomarginata' Fumio Maekawa 1940/AHS 1987 montana sportpulchella 'Aureomarginata' Japan
rectifolia 'Aureomarginata' Japan --->Kifukurin Tachi
Rohdeifolia Aureomarginata
sieboldiana 'Aureomarginata' Gray Cole Nursery/Bob Kuk
tardiva 'Aureomarginata' Japan
ventricosa sportventricosa 'Aureomarginata' Karel Hensen 1985/AHS 1986 venusta 'Aureomarginata' Japan
