I to run a pressurized co2 setup, being an Auto Service Tech I am use to having them around, me having kids that are young and having one in the house kinda hit my nerves we all know what kids are like. But mine sits under the tank. I would go with a real tank learn the msds for it and you should be set know that I have witness a dump of a tank and I don't mean end of tank dump, I mean the pressure release valve built into the tank let go(Its a built in safty device on the tank on the valve), all it does is fill the room with co2, really I am sure you have co2 in your house if you have a fire extinguisher, same stuff thats in it. Really they are harmless its like what someone said about a knife.
Besides thats why you came here you want help on the situation and that is what all us experienced people are here for, and you are young and allowed a riffle that is more dangerous than a co2 tank!
First thing you do with a knife is learn to use it properly
First thing you do with a Riffle is learn the safty of the weapon
First thing you do with compressed co2 is learn about it
(Tell your mom I have a 3 year old and a 6 year old and have 1 in the house already and my 6 year old is getting her own planted tank soon and a co2 tank at the age of 6)
MSDS Information (Material Safety Data Sheet)
http
/www.uigi.com/MSDS_gaseous_CO2.html
Just remember if you have a fire in your house make sure you tell the fire fighters this when they arrive they do need to know you have compressed co2, usually they assume this due to fire extinguishers having co2 in them.