well, it depends on how old it is, how old is it? because if its around a year old or more (or maybe a little under), then yes, thats about right, but if its only like, a couple months old, then no not really, well, ok no i shouldn't say that, well, ok no its not normal, but tbh i'd say its fine, like- ok, to put it in a conflicting way, yes and no, yes because batteries degrade, but no because normally iPhone 11 batteries should last longer than a couple months before reaching 90% health or less, but i don't want to really call it abnormal because like, its probably not defective, its just, "different", idk, sorry for being so unprofessional, its just that this is really hard to answer this in a professional way because its more of an opinion than a fact (my answer to this, and tbh most other answer to a question like this too), so basically, it depends on how old it is, if its a year old or more (or maybe a little under), then yes, its normal, but if its only a couple months old, then no its not normal, and to clarify why this is a hard thing to put into words, its because normal has to be defined in this situation, because if, by asking if its normal, you are asking if its defective, then no, it's probably not defective, but if you are asking if this is, by definition, "normal", then technically yes, ish? but even then its not "normal", but it is normal at the same time, in a sense that batteries do degrade, so yes it is normal, but it shouldn't be degrading this fast,
basically to further clarify and simplify, yes its sort of normal, it just depends on how old it is, if its a couple months old, then no its not normal, if its a year or older (or maybe a little under), then yes, that would normal, i hope this helps and if you have any other questions or comments or anything, feel free to ask/say and i or someone else would love to help your further
