no i dont think you need to go on insulin.
definetly keep an eye on things though, if your fasting levels get into the 7s before you have your GD test then go and see a dr.
If you do end up on insulin, its not so bad, and always remember when your baby arrives you can stop taking it.
If you need any advice just pm me. ive got type 1 diabetes and this is my second pregnancy with it