WPF: MVVM (Model View View-Model) Simplified

<UserControl x:Class="OliverCode.MVVM.View.PersonView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Height="Auto" Width="Auto"
    xmlns:local="clr-namespace:OliverCode.MVVM.ViewModel">
    <StackPanel Orientation="Vertical" Margin="4">
        <!--Here is where we the view gets a copy to the ViewModel Declaratively-->
        <StackPanel.DataContext>
            <local:PersonViewModel />
        </StackPanel.DataContext>        
        <StackPanel Orientation="Vertical" DataContext="{Binding Path=Person, Mode=TwoWay}" Margin="4">
            <StackPanel Orientation="Horizontal">
                <Label Content="First Name:" Margin="0,0,4,0"/>
                <TextBox Width="250" Text="{Binding Path=FirstName}"/>
            </StackPanel>
            <StackPanel Orientation="Horizontal" Margin="0,5,0,0">
                <Label Content="Last Name:" Margin="0,0,4,0"/>
                <TextBox Width="250" Text="{Binding Path=LastName}"/>
            </StackPanel>
            <StackPanel Orientation="Horizontal" Margin="0,5,0,0">
                <Label Content="Age:" Margin="35,0,4,0"/>
                <TextBox Width="50" MaxLength="3" Text="{Binding Path=Age}"/>
            </StackPanel>
        </StackPanel>        
        <StackPanel>
            <Button Content="Save" HorizontalAlignment="Right" Width="80" Command="{Binding Path=SavePersonCommand}"/>
        </StackPanel>
    </StackPanel>
</UserControl>