Welcome, it would be good if you were to give a little more info as to what you consider a sexy mature (but not a granny) to be. TBF I have seen loads of sexy mature women, that have kids old enough to have kids of their own, but wouldn't think of them as grannies, but you might be thinking 28-35 is mature, or you could think 35-55.
If you are an experienced punter, if you can tell us a little about the women you have seen, or if you aren't give us some examples of AW profiles that you like the look of. This will allow the members a much better chance of suggesting someone to you, if they care to at all, asking this type of question in your first post is generally not recommended.