Epi is allegedly anti-estrogenic to some degree, but this allegation doesn't hold true for everyone... I never tried it, just what I read on it. In any case the 100mg TRT will convert to estrogen, but the conversion should be minimal and shouldn't require an AI (at theraputic levels it would be very close to body's natural production and should maintain balance) A SERM, when used for PCT, is usually used to help boost and re-establish natural test production, but since you're on TRT, you wouldn't need that benefit (so, no PCT, just continue TRT)
Another use for a SERM is it binds to the estrogen receptors in your breast tissue, effectively blocking them, so estrogen cannot bind to them (thus making it a good anti-gyno medication) So SERMs prevent estrogen from binding, whereas aromasin (and other Aromatase Inhibitors aka AIs) actually bind to aromatase enzyme which converts testosterone to estrogen, so they effectively prevent estrogen from forming. Those are basically the two ways to manipulate estrogen, you can't "get rid" of existing estrogen, it would have to matabolize out of your system
Generally there's a natural balance of T:E, which is homeostatic, where everything flows smoothly. (body creates a certain amount of test (or u supplement it through TRT), which converts to a certain amount of estrogen, both are useful and healthy to the body in proper proportions) Bottom line, epi should not cause estrogen issues, and the test dose you're taking is probably too low to cause any significant aromatase activity... but it may be a good idea to at least have an AI on hand just in case (aromasin or adex would be fine)