It's just to make it sound more idiomatic in English. Irish, unlike English, doesn't use the perfect a lot, so a lot of Irish translations will translate to the English perfect to be more idiomatic in English, and such is the case here.
It's literally "I am there from the start.", which sounds odd, so they translated it in a more idiomatic way.
This sentence doesn't make sense to me. "There" implies somewhere else, but "I have been ... from the start" implies something that is still ongoing, and I can't "be there" in the present tense, I can only "be here" in the present tense.
Táim anseo is one thing, but Táim ansin? Bhí mé ansin nó beidh mé ansin, b'fhéidir.