No one can tell you if you will actually need an Aromatase inhibitor (AI) as in if sides from estro will appear, but yes they can and , just because you don't have symptoms doesn't mean you don't have high estro.
Don't get me wrong, some elevated estro while on cycle is not a bad thing, a lot people get a lot of strength from water retention caused by estro, but its also not good to have high levels of it.
Do like mentioned above, wait a couple weeks and start with a very low dose, .25mg eod is a good place to start, if you start to get gyno bump to .5mg. Some guys run as much as 1mg a day but I can't handle 1mg eod. If you crash estro, especially on arimidex, you will know, your joints will start to hurt in a lot of places. It can cause bad anxiety, panic attacks, lethargy, etc. high estro can cause a lot of similar sides, no libido, limp dick, all kinds of things.
Guys on testosterone replacement therapy (TRT) which is typically 150mg a week are prescribed up to 1mg a day of arimidex, which is to much in my opinion but then again it depends on a lot of factors.
Can you gain fat easily, or can you eat all day, stay lean and even lose weight? Guys with high body fat produce more aromatase enzymes, which means you will convert more test to estrogen, and typically need more of an Aromatase inhibitor (AI), but no matter what dose of test you are on, your body can only use so much, and its a lot less than people think. Your free test is what's being used by your body, the rest and majority is bound to shbg and albium, which convert test to estro and some is converted to DHT as well.