Eating birthday cakes on birthdays is a customary tradition. Although it is a habit introduced from the West, it is still a good way to celebrate. There is also a link of making a wish. Sweet cakes, plus wishes, are also a very warm birthday meal. As for cakes, I think there are many. You can customize them according to your preferences and your mother's taste.
If your mother likes sweets, you can order Emile's cake, which has many styles. Fruit ones are pretty good. The cream is very fresh and can be eaten with confidence.
If there is nothing special, you can order the Royal. There is a chestnut cake, which is also very good. Generally, mothers of this age will like that taste.
Of course, you can also go to the cake shop to make it yourself, DIY one, and you can also make some blessings you want to say. I believe that your mother will be very moved when she sees your blessings and the cake you made by yourself.