Armidex on first Sustanon cycle

[sleeveless]

Hello there i just joined this forum to seek some advice from more experienced users.

so im 21 year old and i weigh 78kg with 13% body fat.

i started my first ever cycle and i chose to use sustanon 250 and im taking pretty low dosage since this is my first cycle and i wanna see how i react to AAs (350mg a week), i got myself arimidex also.

but heres the question:
im not sure should i start taking arimidex right away like 0.25mg ED or should I wait and see if i get any estro related sides and then start taking it, since my dose is pretty low could arimidex ruin my gains cause of going too low on estro?

thanks in advance!