I like the way you want to feel your mom special on her birthday. It is tough to express love for mothers in words, but you can use several quotes on birthday cards. See these quotes:
"The one who has given me a special life that I presently live, I really can’t imagine how life will be without your guidance. Happy Birthday to you wonderful mother."
If your mother is more than a mother for you and you are best friends for each other, then you can also do with some funny birthday wishes like this.
"I just came over because I smelled birthday cake…and, of course, because I have the greatest mother in the world! Happy Birthday to you, Mom."
On the other hand, if we talk about gifts, then I think you should go with unique ideas. You can give her a surprise by inviting her college time bestie or can make an album of your mom's journey after marriage. Hopefully, your mom will enjoy it.