[Grammar] ....i have watched or watched

[Oceanlike]

- It's the first 3D movie that I have watched.

I thought the answer is 'watched'. I don't understand why the correct answer is in the present perfect tense.

Kindly help me to understand.

Thank you!

 

[Matthew Wai]

I think this is because the present perfect here refers to life experiences, but I am not a teacher.