Radha was never initiated

na dīkṣāsyāḥ śikṣā-śravaṇa-paṭhane vā guru-mukhāttathāpīyaṁ rādhā tri-jagad-abalā-vismaya-bhuvām |kalāmbhodheḥ śaurer api parama-santoṣaṇa-kṛtāṁkalānām ācāryā vraja-mṛga-dṛśām apy ajani sā ||

Our Radhika was never initiated, nor did she take any lessons from a shiksha guru. Even so, she has become the acharya from whom the doe-eyed Vraja sundaris learn all the arts of satisfying the heroic artist himself, Krishna, arts that are the source of amazement to every other attractive damsel in the three worlds. (GLA 11.124)