All subsections except first one are indented. How do you align them?

Question

I am trying to figure out why my subsections are not aligning with the rest of my document. I is displaying that all the subsections following the first one are indented.

\documentclass[12pt]{article}
\usepackage[english]{babel} %sets the language to English
\usepackage[text={7in, 9in}, centering]{geometry} %sets up the dimensions where text will 
%be written within the doc.  showframe will show the magian frame.
\usepackage{ragged2e} %improves left justification of paragraphs
\usepackage{amsfonts} %loads extra fonts and symbols, including boldface (\mathbf),             blackboard boldface (\mathbb), and fractur (\mathfrac) 
\usepackage{array}
\usepackage{enumerate}
\usepackage{tikz} %allows for you to draw venn diagrams
\setlength{\parindent}{0cm}

\begin{document}
\section*{Solutions}
\subsection*{1.2}
\begin{enumerate}
\setcounter{enumi}{3} %count at 4
\item a
\setcounter{enumi}{13} %count at 14
\item a
\setcounter{enumi}{19} %count at 20 
\item
\begin{enumerate}[a)]
\item a
\item a
\end{enumerate}
\subsection*{2.1}
\setcounter{enumi}{3} %count at 4
\item
\begin{enumerate}[a)]
\item  a
\item  a
\end{enumerate}
\end{enumerate}
\end{document}

Answer 1

Does this do what you want?

\documentclass[12pt]{article}
\usepackage[english]{babel} 
\usepackage{array}
\usepackage{enumerate}
\setlength{\parindent}{0cm}

\begin{document}
\section*{Solutions}
\subsection*{1.2}
\begin{enumerate}
    \setcounter{enumi}{3} %count at 4
    \item a
    \setcounter{enumi}{13} %count at 14
    \item a
    \setcounter{enumi}{19} %count at 20 
    \item
        \begin{enumerate}[a)]
            \item a
            \item a
        \end{enumerate}
\end{enumerate}

\subsection*{2.1}
\begin{enumerate}
    \setcounter{enumi}{3} %count at 4
    \item
        \begin{enumerate}[a)]
            \item  a
            \item  a
        \end{enumerate}
\end{enumerate}
\end{document}

As Werner said, you have a problem of enumeration spanning across the subsection. If you open and close your enumerate environment, the problem should be fixed.