If you mean "struck" as "seemed to be", both can work.
Student or Learner
Which one of the following sentences is correct, or both acceptable?
1. Mary struck me as childish.
2. Mary struck me as a childish person.
Would this be better?
1. Mary struck me as being childish.
I am not a teacher.
Often usage comes down to personal preference. For example, I would prefer:
Mary's behavior struck me as childish.