So, I recently picked up a .tex-template from some website and added some stuff for my own needs. For some reason the counter starts from 2, and I've attempted some counterresets found online without luck.
MWE
\documentclass[paper=a4, fontsize=11pt]{scrartcl}
\usepackage[T1]{fontenc}
\usepackage{fourier}
\usepackage[english]{babel}
\usepackage{amsmath,amsfonts,amsthm}
\usepackage{lipsum}
\usepackage{sectsty}
\allsectionsfont{\centering \normalfont\scshape}
\usepackage{fancyhdr} % Custom headers and footers
\pagestyle{fancyplain} % Makes all pages in the document conform to the custom headers and footers
\fancyhead{} % No page header - if you want one, create it in the same way as the footers below
\fancyfoot[L]{} % Empty left footer
\fancyfoot[C]{} % Empty center footer
\fancyfoot[R]{\thepage} % Page numbering for right footer
\renewcommand{\headrulewidth}{0pt} % Remove header underlines
\renewcommand{\footrulewidth}{0pt} % Remove footer underlines
\setlength{\headheight}{0pt} % Customize the height of the header
\setlength\parindent{0pt}
\newcommand{\horrule}[1]{\rule{\linewidth}{#1}}
\theoremstyle{plain}
\newtheorem{theorem}[subsection]{Theorem}
\newtheorem{conjecture}[subsection]{Conjecture}
\newtheorem{proposition}[subsection]{Proposition}
\newtheorem{lemma}[subsection]{Lemma}
\newtheorem{corollary}[subsection]{Corollary}
\theoremstyle{remark}
\newtheorem{remarks}[subsection]{Remarks}
\theoremstyle{definition}
\newtheorem{definition}[subsection]{Definition}
\newtheorem{exercise}{Exercise}
\newtheorem{remark}{Remark}
\title{
\normalfont \normalsize
\textsc{} \\ [25pt]
\horrule{0.5pt} \\[0.4cm]
\huge Notes for Some Subject \\
\horrule{2pt} \\[0.5cm]
}
\author{Some Guy}
\date{\normalsize Spring 2015}
\begin{document}
\maketitle
Notes for a course in Blabla.
\section{Representations of finite groups}
\subsection{Blah}
% This becomes definition 1.2
\begin{definition} A {\it group}
\end{definition}
\end{document}
subsection
counter for numbering the theorems, and not a general counter for theorems.