The sentences compares the ages of two people. The word we use when comparing is “than.” We say “larger than,” “closer than,” “worse than,” etc. This is true whenever we are comparing degrees of some quality such as distance, tastiness, number, beauty or age.
Indians, for some unknown reason, came to use “to” instead of “than” in some comparisons, but this is not standard.
The second sentence is incorrect. It ends in “me” instead of “I.” Whenever you compare the age, intelligence, wealth, beauty, strength or other quality, you are saying, “They are more/less X than he is.” (I am, she is, we are, etc.) You don’t have to say the “is” at the end, but you should keep it in mind so you don’t substitute me/him/her/us/them for the correct I/he/she/we. “Me am” “him is” “her is” and “us are” are incorrect, and they sound wrong.
He is younger than me am.
He is younger than I am.
You should see instantly that the second sentence is the correct one. If you decide not to say the ‘’am” at the end, you still should use “I” and not change it to “me.”