First indent is shorter than it should be

Question

I am using \paragraph{} at the beginning of chapter. All my paragraphs are intended automatically but first indent is always little bit shorter than others (I mean that white space). Does anyone experienced this problem before? I have no idea what's wrong

\documentclass[a4paper,12pt,oneside,onecolumn,final,openany]{report}
\usepackage[utf8x]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[slovak]{babel}
\usepackage{ae}
\usepackage{fancyhdr}
\usepackage{graphicx}
\usepackage{makeidx}
\usepackage[top=2.5cm, bottom=2.5cm, left=3cm, right=2.5cm, includefoot]{geometry} %total={17cm,25cm},
\usepackage{longtable}
\usepackage{amsthm}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{textcomp}
\pagestyle{fancy}
\usepackage{hyperref}
\usepackage{float}
\usepackage{subfig}
\usepackage{booktabs, multicol, multirow}
\usepackage{bigstrut}

\begin{document}

\def\baselinestretch{1.2}\normalsize

\chapter*{First one}

\paragraph{}
\bigskip

{\bf First} - aaaaaa\\

{\bf Second} - bbbbbb\\

{\bf Third} - ccccccc\\

\end{document}

Answer 1

\paragraph is a sectioning command, just as \chapter, \section etc, it is not intended for starting a new paragraph -- an empty line does that (or \par).

In the standard classes, there is no indentation of the first paragraph of a chapter/section (why should there be?), but the \paragraph command adds some space. Hence, what you're seeing is not paragraph indentation, but space added by the \paragraph command.

If you really want to indent the first paragraph, use indentfirst as mentioned by Mario, and remove the \paragraph{}.

\documentclass{article}
\begin{document}
\section{First section}
First paragraph. Not indented.

Second paragraph, indented.

\paragraph{Lower level heading}     \texttt{paragraph} is below \texttt{subsection} (and \texttt{subsubsection}).

\section{Second section}

\paragraph{} \texttt{paragraph} used wrongly, note extra space.
\end{document}

Answer 2

I think you can use the indentfirst package by David Carlisle (available here) and then call it on your preamble:

\documentclass{report}

\usepackage{indentfirst}

\begin{document}
\chapter{First Chapter}
Hello.

This is my second paragraph.

\end{document}