Mom has been to Amanome several times. What gift should I give or say to make her happy?

It should be normal to hear that mom is going to have a birthday.

So you can give any gift. The key is your thoughts.

If your family is romantic at ordinary times, you can send her a bunch of roses.

If your mother is that kind of pragmatic person, you can give her a pair of warm shoes or a coat.

Of course, you should also consider your own actual situation. If you are just a student and have no consumption level, or your mother is frugal and doesn't like to accept these expensive things, you can say something happy, such as writing a note or saying thank you that day. For example, thank you for raising me so much and cultivating me. These are all sincere. As long as you mention that you remember something about your mother at your age, I feel very moved.