。
I'm slow to adapt to new environments.
Literal
I [topic-は] new environment [to-に] adapt [nominalizer-の] [subject-が] slow.
順応する (じゅんのう, 'to adapt, adjust') is a Sino-Japanese する verb. The nominalized clause ~のが is the subject of 遅い — 'the act of adapting is slow for me.' A natural way to describe a personal tendency.