How to Coordinate Multiple Uses of footnotemark and footnotetext in a Tikzpicture Environment

Consider

documentclass[12pt]{book}
usepackage{tikz}
usetikzlibrary{decorations.pathmorphing}
begin{document}
thispagestyle{empty}
begin{center} 
begin{tikzpicture}[pencildraw/.style={ %
    decorate,
    decoration={random steps,segment length=2pt,amplitude=1pt}
    } %
]
node[
preaction={fill=black,opacity=.5,transform canvas={xshift=1mm,yshift=-1mm}},
pencildraw,draw,fill=blue!25,text width=0.94textwidth,inner sep=5mm,align=justify] 
{fontsize{13}{18}selectfont textbf{First sentence.footnotemark , Second sentence.footnotemark , Third sentence.footnotemark}};
end{tikzpicture}
end{center}
footnotetext{first footnote}
footnotetext{second footnote}
footnotetext{third footnote}
end{document}

which produces the tikzpicture

with the footnotes

QUESTION: How may I correct the above code so that the correct footnote marks (1 followed by 2 followed by 3) appear in vertical sequence?

Thank you.

footnotetext[1]{first footnote}
footnotetext[2]{second footnote}
footnotetext[3]{third footnote}

documentclass[12pt]{book}
usepackage{tikz}
usetikzlibrary{decorations.pathmorphing}
begin{document}
thispagestyle{empty}
begin{center} 
begin{tikzpicture}[pencildraw/.style={ %
    decorate,
    decoration={random steps,segment length=2pt,amplitude=1pt}
    } %
]
node[
preaction={fill=black,opacity=.5,transform canvas={xshift=1mm,yshift=-1mm}},
pencildraw,draw,fill=blue!25,text width=0.94textwidth,inner sep=5mm,align=justify] 
{fontsize{13}{18}selectfont textbf{First sentence.footnotemark , Second sentence.footnotemark , Third sentence.footnotemark}};
end{tikzpicture}
end{center}
footnotetext[numexprvalue{footnote}-2]{first footnote}
footnotetext[numexprvalue{footnote}-1]{second footnote}
footnotetext{third footnote}
end{document}