Welcome to the wonderful world of sailboat ownership!
Here is the general spec of your Irwin 27'
Notice in the above link that they describe your boat as "keel/ctrbd", so your boat has a center board, not a drop keel (swing keel) or dagger board.
These terms get misused a bit so I'll say what I think each one really means.
1) Swing keel - this set up is really a very heavy center board. Swing keels can weigh around 1000#s and thus need very robust lifting mechanism. A swing keel provides ballast at the lowest point and helps the boat stay upright.
2) dagger board - in this case the board is quite light weight and is inserted vertically into the hull by hand. Many dinghy sail boats use this arrangement.
3) Center board - center boards pivot (as do swing keels) into a slot in the hull but their weight is nominal (< 200 #s) providing little or no ballast or righting moment.
All 3 types of board allow a boat to head upwind but only a swing keel provides a heavy ballast below the water line.
As to your specific center board's operation I can't say. Look for a line that disappears into the bottom of the boat near the engine compartment. On my boat the center board pennant is routed into the cockpit and, yes, even my wife could lift it or lower it. There is some mechanical advantage built into our lowering/raising mechanism.