Well, it is not directly a bad decision. It takes time to gain some skill in this game. That applies for both archery and melee combat. Archery is usually the first choice of new players as you don't directly have to go into melee combat. Never forget to use a sword (or any other 1 handed weapon) when going with a bow. It is important that you are able to block your enemies. Without a melee weapon you cannot even defend yourself.
(read guides for the way how to skill your character and other useful tips
)
As you already know about retirements it is maybe also useful to know that loomed stuff improves the items' stats. Good example is your bow, more speed, more dmg, so really useful to loom it. People often claim that the only good archers are fully loomed (bow, arrows) and that is partly true. Every additional dmg point is really useful, but it also works without, depending on your own skill which improves in time.
Dont give up if you die quickly in melee, many people play this game for months, over a year or even up to two years or above since warband was released (and in beta). And they play on a daily basis. ;)
The first generations take some time to pass as you only get 1000 xp per tick as zagibu already said. With every retirement you get 30 xp more per tick which saves you 4 hours (while having x1).
For the first gen you will need about 80 hours, totally depending on your multiplier. You will often have x5 for some rounds or even maps, most times around x1 or x2 though.
Archers are needed in Strategus as range is always important, be it in a defense or attack of a castle or a simple field battle where archer support is really important for melee combat.
Also note that Strategus is a team game. You either need to be in a Strategus faction, a group of many people or even better in a clan for both Strategus and crpg.
PS: Regarding the "bad decision". You must know that Archers are really hated by many players.