We all have doubts about our abilities and feeling a little overwhelmed when entering a new job or career. I wouldn't put off student teaching at all. The only way to find out if this is the right career choice, and, more importantly, find out about yourself, is to give it a whirl immediately. Any delay will only cause more agonizing and uncertainty. If you find you don't like it, work through it while working towards another career.
I was a degreed computer professional a # of yrs. ago. I found out very quickly I hated sitting in an office cubicle behind a computer all day. I fought through it while studying for a career change. Now I work as a high- skilled precision CNC machinist for a small company, and I love my job. Sure, I may have become very wealthy when the internet exploded on the scene, but I knew I was going to be absolutely miserable. To me, there is more to peace of mind than just a fat pocketbook.
Additionally, it is no small fact that people these days and well into the future will make a # of job moves and career changes. Its all a part of maturing as an individual, learning from life, and finding what makes you happy and not what makes you fat in the bank account.
Don't be concerned about your misgivings. We all have them. Just remember, the path you have chosen will always have exit ramps.
Good Luck.