If your midwives aren't concerned about your weight gain, I wouldn't be, either.
As for the "reset," you may find that it occurs, anyway. I was around 200 pounds when I became pregnant with my first and gained around 35 pounds over the course of the pregnancy. I asked if I needed to gain "less" due to my weight at the beginning of pregnancy and was told that they recommended a gain of 25 to 45 pounds and I might want to shoot for the lower edge of that, but it wasn't an issue.
I lost ALL of the baby weight almost immediately (I'd say within about two weeks of the birth). By the time DD was a little over a year old, I was holding steady between 180 and 185, and she was around 14 months when I became pregnant again. I'm now 19 weeks with #2 and although I feel I "show" more than I did with DD, I have yet to begin actually gaining in this pregnancy. You can actually tell I'm losing weight elsewhere still and "moving" it to my belly! And I eat SOOOO much more this pregnancy, also lots of red meats, etc., as that is what I crave. So if it's like my last pregnancy, and I lose the "baby weight" right off again, I would likely be in a target weight range and no longer even overweight pretty soon after baby arrives, if you consider that I could potentially lose around another 30 to 35 pounds or whatever my body is actually using for the baby. I was just thinking today that when I need to shop for maternity clothing, which could be soon, I could actually find myself having to buy maternity clothes in a size or two smaller than the clothing I needed just before I got pregnant. I actually changed clothes at lunch today because I was wearing a pair of shorts that had quickly become tight and bothersome during my last pregnancy (I'd say by 10 weeks), and they were actually falling down on me at 19 weeks pregnant this time around.