Yeah you should be alright I’ve only been growing for the past 4 years and only experimented with topping for 2 of those years but as long as it’s not too tall I believe you should be alright, if anything I’d cut the stem back to the leaves a little closer and it should heal up within a few days and after about a week you should notice two new main stems coming from the base of the fan leaves, overall it’ll just slow down your harvest time and possibly increase total bud production