First of all, welcome

I also have read that EDs are more common in teenagers. However, as with most illness, it may be more common then, but can also occur outside of the usual time. Measles, for example, usually strikes in childhood but adults can get it too. I'm sure you have read that EDs can strike at any age... You're not different in any way because of starting later. I think it is mainly that younger children/teenagers get the attention because they are minors and so need treatment, whereas adults can choose whether or not to go to a doctor, and so may never be officially diagnosed, and their doctor may never learn of any eating issues.