"I am waiting for my children."
Translation:J'attends mes enfants.
All verbs at all tenses and moods have an -s when the subject is "tu".
The only exception is in imperative, for verbs of which infinitive ends in -er (1st group)
For "je" all verbs from the 1st group end in -e in indicative present. All other verbs end in -s except "avoir" (j'ai).
It is not incorrect in absolute, since indeed "expect a child" is "attendre un enfant". But in this sentence, this specific meaning would not work.
Remember that when you hover on words and get a glossary, you are given several translations that can work in a number of instances, but not necessarily the right translation for the sentence you are working on.
I am waiting is a continous present tense.
French does not have continuous tenses.
Therefore "I am waiting" and "I wait" can translate to a simple present tense "j'attends".
Besides, unlike "to wait for someone/something" the verb "attendre" does not need a preposition to introduce its object, so "attendre quelqu'un/quelque chose".