In English, you say:
It took some (serious) getting used to, but ...
... with the word "some" acting like an intensifier. This colloquial structure essentially takes the form of "It took some + gerund, but ...".
What is a commonly used phrasing in Russian to express this idea? Does the following sound idiomatic enough?
Привыкнуть к этому мне удалось уж точно не сразу, но ...