Hi Carol I am so very sorry for your loss.  I can't imagine how painful it must be to lose a child.  I do believe he is definitely in heaven now with our Lord.
 
I wanted to give my opinion as to why I believe children/youth can go into heaven if they die before twenty years old according to what the Lord had said regarding the children going into the promised land:
 
Numbers 14:27-31 (KJV)
27 How long shall I bear with this evil congregation, which murmur against me? I have heard the murmurings of the children of Israel, which they murmur against me.
28 Say unto them, As truly as I live, saith the Lord, as ye have spoken in mine ears, so will I do to you:
29 Your carcases shall fall in this wilderness; and all that were numbered of you, according to your whole number, from twenty years old and upward, which have murmured against me,
30 Doubtless ye shall not come into the land, concerning which I sware to make you dwell therein, save Caleb the son of Jephunneh, and Joshua the son of Nun.
31 But your little ones, which ye said should be a prey, them will I bring in, and they shall know the land which ye have despised.

Ok, so we know teenagers and their mouths and attitudes, right?  Well, I imagine they murmured against the Lord at this time also.  But, they were not held accountable.  So if the Lord didn't hold anything against the children and allowed them to go into the promised land, and with us under a better covenant- mercy and grace - I honestly believe chldren go into the promised "heaven" when they die before 20 yrs old.  20 years old is considered age of accountability I think.  That's the age they were to start serving in the temple,  etc.  
 
Exodus 30:14 (ASV)
14 Every one that passeth over unto them that are numbered, from twenty years old and upward, shall give the offering of Jehovah.
Exodus 38:26 (ASV)
26 a beka a head, that is, half a shekel, after the shekel of the sanctuary, for every one that passed over to them that were numbered, from twenty years old and upward, for six hundred thousand and three  
thousand and five hundred and fifty men.
 
Leviticus 27:3 (ASV)
3 And thy estimation shall be of the male from twenty years old even unto sixty years old, even thy estimation shall be fifty shekels of silver, after the shekel of the sanctuary.


These are just some of the scriptures establishing worship, offering, etc. I hope this helps give you peace.
 
 
 
I know some people think you have to make a choice by 12 years old based upon Jesus teaching in the synagogue but not me...
 
Blessings and may God give you the dream/vision you want to comfort your heart during this time.  May He wrap you in His loving arms and give you His peace.
 
 
Sherry