I never miss a Hockey match. I __________ fond of it since my childhood.

The phrase since my childhood denotes a state that began at a point in the past and continues up to the present, which requires the present perfect tense. With the first-person singular pronoun I, the correct present perfect form of the verb be is have been. The simple present am cannot be paired with a since time clause, has been is the third-person singular form, and the future tense will be conflicts with a past starting point.