Nah. Balance between units at this point in the game's history is actually some of the best. It used to be that spamming Long Range Frigates (LRF) would win most any game. Then with Rebellion's beta came Corvettes. They're pretty balanced now, but at one time they could knock out pretty much anything in their path. Now you can't really spam anything* to win because you'll be countered. Corvettes>LRF>Light Frigates (LF)>Flak>Corvettes.
You can't choose the starting position unless you make your own map in a program included in the download called Galaxy Forge. You can pick the faction and difficulty of each player though as well as game speeds and victory conditions.
Also for a noob, I recommend disabling pirates. Getting hit by them first can really put a dent in your expansion. Late-game, they're just exp for your capitals and titan, but early on they are pretty brutal. Honestly, most MP games disable them anyways.
You can always play MP compstomps as it allows you to get real-time feedback from other players. Also, what level of AI were you going against?
*There is of course an exception to this. Late-game you can spam light carriers (LC) and load them up with bombers. You will eventually reach a point known as "critical mass" at which point they will kill anything in their first pass. That is the only IWINBUTTON in the game (contrary to some of the people in the SP community who complain about superweapons being OP because they aren't and are easily dealt with).
Head over to the strategy section and read up a bit. Most things are a bit outdated, but you should get the gist of things.
As for your playstyle, I recommend the TEC Loyalists as they focus on turtling not to mention the TEC is the most straightforward race in the game and thus is the best for new players.