There are advantages to starting with a small agency that you wouldn't get in a large city. Small agencies need the officers to do a little bit (or a lot) of everything, so you'll learn patrol, criminal investigation, crime scene evidence collection, arrest procedures and case preparation for trial. You'll likely learn to do your own probable cause affidavits for warrants, and you may have a few kicked back by a magistrate because you left out a key word here or there. In big agencies, there are office dweebs who handle the paperwork while patrol acts as a taxi service to bring folks into the jail and dump them. On the down side, you may be the only officer on the street at times with the nearest backup 15 - 20 minutes away. You'll learn some creative techniques to keep your hide intact while awaiting help.
My last position was with a small sheriff's office. We had 8 deputies when I started here, not enough for 24 hour coverage. That meant whoever lived close to the call got called out in the middle of the night. One riot, one ranger. Twenty minutes minimum for backup to arrive. On the rare occasion when someone was drunk enough to want to fight, I pointed to my handheld radio with a little red button on top. I told the guy "If I have to push that little red button, it will rain police for an hour, and they won't be happy getting dragged out of bed." He decided to go peacefully. Good thing, because that little red button didn't do anything, and the handheld radio was worthless that far from the repeater.
My last position was with a small sheriff's office. We had 8 deputies when I started here, not enough for 24 hour coverage. That meant whoever lived close to the call got called out in the middle of the night. One riot, one ranger. Twenty minutes minimum for backup to arrive. On the rare occasion when someone was drunk enough to want to fight, I pointed to my handheld radio with a little red button on top. I told the guy "If I have to push that little red button, it will rain police for an hour, and they won't be happy getting dragged out of bed." He decided to go peacefully. Good thing, because that little red button didn't do anything, and the handheld radio was worthless that far from the repeater.