I do not have good balance or hand-eye coordination either. I started with a hybrid, and eventually put road tires on it. I love my LBS - they are VERY supportive and encouraging. My husband is supportive as well, although he is very athletic and does not understand some of my issues, and was very confused when I kept falling after I got clips. I felt very unsure of myself for over two months. I was about 180 pounds when I started riding. My butt hurt, my hands and wrists hurt, everything hurt. I just kept going three times a week, and as my core got stronger everything got better. I have lost 35 pounds and ordered a road bike - the LBS guys say I am ready and deserve it. I would just keep going into the shop and asking questions. When they see you are persevering I am sure they will be more supportive. Try to find a no drop group ride - luckily my LBS has one twice a week and the group is very helpful. Hang in there - it will get better!
Karen
2009 Cannondale Quick 4 Hybrid
2010 Periwinkle Trek Madone 4.7 WSD, Bontrager Affinity 2 WSD Saddle
2012 Co-Motion "Speedster" Tandem with Lady Selle Italia Saddle and thud-buster
lesko.tumblr.com