I agree with everyone here. Trust your gut. Those stories of big babies for women with diabetes include those with type 2 who do have a harder time keeping BGs inline during pregnancy. If you can keep your A1C in the low 6s or 5s, your baby shouldn't be any bigger than they it would if you didn't have type 1.
My a1c was kept in the high 5s for most of my two pregnancies. I had a 6lb 6oz daughter at 38 weeks the first pregnancy and 6lb 9oz daughter at 38 weeks for the 2nd pregnancy (the ultrasound tech said this baby was "well over 9lbs" four days before I was induced - just happens my husband has a big head and my girls had 95th percentile heads ;-). Both were 18.5". I was 6lb something when I was born any my husband was in the high 7lb range. At this point in time, I'd take your & your husband's family history more into play on baby size (pending you are able to keep your A1Cs down) than BG.
My best advice is to take in everything they say, ask questions about every single thing ("why is that?" was my favorite line) and if you want something a specific way (i.e. you want to do everything possible to delivery vaginally) be sure they know that. It's still your body and you know it WAY better than any doctor does.
I will also let you know, that both of my daughters did need to have glucose put into their stomachs with a tube after birth because their BGs got too low (their little bodies are used to covering for our 'high' (every 150 is "high' to an infant in your womb)). It was a one time deal for both and they both had no trouble after that one bolus.