There is a list of coaches on this forum. Why not find one and work with them IN PERSON for one or two times on your form? You will find that it is worth the money (some will help your free if it's just once or twice) and it will result in you rowing correctly/efficently.
You are excited - that's normal. Trouble is you may find yourself training too hard to the point of overtraining or injury. Take it easy and vary your workouts.
Consider cross-training, but work your
whole body on different pieces of equipment. By working the large muscle groups in your body the weight will come off.
Overtraining: after working out for a while you should get a "high." If you find that you are tired, waking up in the middle of the night or irritable - it's time to back off a bit. No big hurry to lose the 10-15 pounds that you say you want to take off.
Many new rowers set the damper setting too high to increase the resistance thus making them work out harder. As a newby, you should set it in the 4 to 5 setting. With proper form (learned from a coach) you will bring your split times down. Keep things fun and you will really enjoy it.
If it gets boring - row in front of the TV or get yourself some headphones. Set goals and do the challenges.
I'm a former fat boy still trying to lose 30 pounds (I've lost about 60). Thus - I'm just a SMALLER fat boy!! However, I'm working to develop the body that men fear and women love.

Takes time to do that and it's worth it!!