Since children and teenagers (minors) conversions are not recorded in the entire New Testament, I always wondered if they were qualified candidates for Christianity.
Suffer the little children to come unto me, for such is the kingdom of God. (Paraphrased)
It is entirely the opposite. Unless you are converted and become as one of these little ones, you shall in no wise enter the Kingdom of God.
Mar 10:13-16 And they brought young children to him, that he should touch them: and his disciples rebuked those that brought them. (14) But when Jesus saw it, he was much displeased, and said unto them, Suffer the little children to come unto me, and forbid them not: for of such is the kingdom of God. (15) Verily I say unto you, Whosoever shall not receive the kingdom of God as a little child, he shall not enter therein. (16) And he took them up in his arms, put his hands upon them, and blessed them.
I do realize, that you make the special case of qualifying 'teenagers' in your post, as well as children in general. I can only attribute this to some notion of accountability, which in Jewish tradition is , I believe, age 13. I do not see any support for this as a regulatory restriction, in any terms of eligibility for salvation.
There is certainly not a single mention in all of scripture that would support this idea that children would, of all souls, ever be denied by Jesus Christ; Old or New.
I will say in response to the question of some ineligibility; emphatically, no.