I am thinking about if I should get H.G or S.S or not. I have some question about them.

1.Can you trade Pokemon with any other D.S(I have an origional D.S and my brother has a D.S.I)

2.Can you battle other people over other D.S consoles?(do you have to be next to them or is it worldwide)

3.How long is the game?

4.Which game is better and why?

5.Am I to old for Pokemon?(Teen)

1) Yes
2) Yes
3) Cant give you an exact time but have a look on a Pokemon fansite with a HGSS guide as itll show you all the stuff you can do ingame which will give you a feel for the length
4) Both games are really the same except for some version exclusive Pokemon and which legend you get first. Most people will get Heart Gold simply because its name comes first

5)I'm 20.Which means I should be adult. I loved the original silver game.So I'm gonna play this one.

1.Can you trade Pokemon with any other D.S(I have an origional D.S and my brother has a D.S.I)

Yes, you can.

2.Can you battle other people over other D.S consoles?(do you have to be next to them or is it worldwide)

Yes, Wireless works for about 15 feet or so.  Otherwise, you'll have to do it via Wi-Fi.

3.How long is the game?

The initial quest can take anywhere from 40 to 50 hours depending on your skill/party.  It can be played for much longer though.

4.Which game is better and why?

HeartGold because of the exclusive Pokémon in that version.

5.Am I to old for Pokemon?(Teen)

No, if you have an open mind to it.

Is it worth the $40?

What i really want to know is there is actually somthing to do in Kanto now? In the original games, most of the side quests, minigames, and plot points were in Johto, while Kanto was a baren land with nothing but 8 gyms.

Oh, and can you play online real time battles against Platinum users?