XSLT: Add node, if it is missing, in a specific place in output XML

I'm trying to build a transformation that will:

• Add a "default" node, if that node is found not to exist within an instance of a parent


• Add that default node in a specific place in the output XML

For example, if "Age" is not provided for a person then it should be defaulted to "Unknown" in the node following the required "Name" node:

<People>
    <Person>
        <Name>Bob Smith</Name>
        <Age>34</Age>
        <Gender>Male></Gender>
    </Person>
    <Person>
        <Name>Jane Smith</Name>
        <Gender>Female</Gender>
    </Person>
</People>

Becomes:

<People>
    <Person>
        <Name>Bob Smith</Name>
        <Age>34</Age>
        <Gender>Male></Gender>
    </Person>
    <Person>
        <Name>Jane Smith</Name>
        <Age>Unknown</Age>
        <Gender>Female</Gender>
    </Person>
</People>

I have the following XSLT, which correctly adds the default, but it adds the default to the end of the Person section. I need the node to be added just after the Name node:

<xsl:stylesheet version="1.0"
    xmlns:xsl="http://ift.tt/tCZ8VR"
    xmlns:p="http://ift.tt/1tABcLP">
    <xsl:output omit-xml-declaration="yes" indent="yes" />
    <xsl:strip-space elements="*" />
    <xsl:template match="node()|@*">
        <xsl:copy>
            <xsl:apply-templates select="node()|@*" />
        </xsl:copy>
    </xsl:template>
    <xsl:template match="Person[not(Age)]">
        <Person>
            <xsl:apply-templates select="node()|@*" />
            <Age>Unknown</Age>
        </Person>
    </xsl:template>
</xsl:stylesheet>

Could anyone help me implement the additional requirement for the "Age" node to be added after the 'Name" node?

Many thanks!