Yes, it's true.
"A is as tall as B" is generally used to mean "A is equally tall or taller than B".
If you want to make it clearer, you can say "A is at least as tall as B".
"Tom is at least as tall as any student in my class."
If you want to mean exactly the same, you'd say "A is the same height as B", or you could use adverbs: "A is exactly/precisely as tall as B"
Student or Learner