diff --git a/src/main/java/dev/kske/undoredo/ChangeManager.java b/src/main/java/dev/kske/undoredo/ChangeManager.java
index 6d520c2..4d45bd5 100644
--- a/src/main/java/dev/kske/undoredo/ChangeManager.java
+++ b/src/main/java/dev/kske/undoredo/ChangeManager.java
@@ -15,8 +15,8 @@ public final class ChangeManager<C extends Change> {
 
 	private final List<C> changes = new LinkedList<>();
 
-	private int	index;
-	private int	markedIndex;
+	private int	index		= -1;
+	private int	markedIndex	= -1;
 
 	/**
 	 * Applies the given change and appends it to the change list.
@@ -27,6 +27,7 @@ public final class ChangeManager<C extends Change> {
 	public void addChange(C change) {
 		change.apply();
 		changes.add(change);
+		++index;
 	}
 
 	/**
@@ -81,7 +82,7 @@ public final class ChangeManager<C extends Change> {
 	 * @since 0.0.1
 	 */
 	public boolean isUndoAvailable() {
-		return index > 0;
+		return index > -1;
 	}
 
 	/**