What variety of maple is it?
And yes... it should always be left outside. You can bring it in for a day or two to enjoy, but no more.
Generally trees which have been collected should be left alone for at least a year or two... so don't plan on doing anything with it anytime soon. Just keep it watered.
Generally most deciduous trees are not collected at this time, but if it's been very cool where you are it will likely be fine... Try and collect deciduous trees before they break leaf or late in the fall after they have dropped leaf.
The chances of it dying are directly relative to the care you give it.
Read the comments in this thread for some good information on general bonsai horticulture....
La belle cose prendono tempo... (Beautiful things take time...)