Hi! From the numbers you have posted, it looks like you would be diagnosed with GD at almost any practice you went to. (Sorry!

)
105 is considered to be a high fasting number. Most guidelines suggest that fasting numbers of 70-85 are optimal. A lot of practitioners recommend starting insulin or a medication like Metformin or Glucophage at fastings above 95.
Generally, post-prandial (after meal) numbers are supposed to be below 140 one hour after the
end of a meal, and below 120 two hours after the
start of a meal. So, again, you are a bit high.
This does not have to mean the end of a healthy, happy pregnancy, and it does not rule out having a good birth! Talk to your practitioner about this. Ask what their approach to GD is. If you hear "Women with GD usually need to be induced" or "GD makes it highly likely that you will have a huge baby" or "GD mothers should never be allowed to go past 40 weeks gestation" or "GD mothers need more monitoring during birth" or anything that sounds wrong, consider finding another practitioner! I left my original practice around 20 weeks, and found a midwife who helped me have a terrific birth experience!
Do you need the 3-hour test? No. It's nasty, and if you're willing to do daily sugar testing anyway, it's irrelevant. The daily monitoring is much more informative than the test. But it's not like you will escape your practice's attention just because you didn't take the test. They've probably already flagged your chart due to the high one-hour test result. So I would be upfront about it, and get the full scoop on how you will be treated if you have GD.
Should you try to manage GD on your own? You can definitely give it a try and see what your levels are! Going on the GD diet is not hard, and getting more exercise is a great idea regardless of your GD status.
Here are the guidelines I followed, with meal examples:
-Breakfast: 15-30 g complex carbohydrates plus some protein (think half a cup of oatmeal with plain soy milk and a hard-boiled egg)
-Walk at least 10 minutes (I was actually walking 30-45 mins)
-Snack: 15 g complex carbohydrates plus some protein (nuts and raisins)
-Lunch: 30-45 complex carbohydrates plus some protein (think turkey sandwich on whole wheat)
-Walk again
-Snack: complex carbohydrates plus some protein (nuts and raisins again)
-Dinner: 45 g complex carbohydrates plus some protein (1/2 cup couscous with grilled chicken breast)
-Walk again
-Bedtime snack: 15 g complex carbohydrates plus some protein (cheese and crackers)
I hope that a little work on your diet and exercise regimen will bring your numbers under tight control. Good luck!