indraḿ nas tvābhiṣekṣyāmo
brahmaṇā coditā vayam
avatīrṇo 'si viśvātman
bhūmer bhārāpanuttaye
indram -- as Indra; nah -- our; tva -- to You; abhishekshyamah -- we shall perform the bathing ceremony of coronation; brahmana -- by Lord Brahma; coditah -- ordered; vayam -- we; avatirnah asi -- You have descended; visva-atman -- O Soul of the universe; bhumeh -- of the earth; bhara -- the burden; apanuttaye -- in order to alleviate.
Surabhi makes it quite clear in this verse that she has had enough of the leadership of imperfect demigods like Purandara (Indra), and now she is determined to directly serve the Supreme Lord. Since Brahma has ordered her, her attempt to coronate Lord Krishna as her personal Lord is authorized by higher authority. Moreover, Lord Krishna Himself comes down to the earth to relieve the burden of self-destructive, mundane administration, and thus it is perfectly consistent with the Lord's own purpose that He become the Lord of Surabhi. Since the Lord rules millions of universes, He can certainly take care of mother Surabhi.
In fact, Surabhi wanted to bathe the Lord for her own purification, and she earnestly makes her proposal to Visvatma, the Soul of the universe, Sri Krishna.