Just Did my First Pin!

Hey guys just did my first inection I am running 400mgs aweek of test e. I frontloaded the first shot at around 520-550mgs split it into 2 shots. Plan on running the Test for 10weeks and starting anavar for 6-7 weeks at some point around week3. I have a question should I start aromasin immediatley and at what dose?

Start 12.5mg ED