My answer is going to be a bit different. Now let me start this off by saying if it is YOUR CHOICE THEN IT IS YOUR CHOICE AS THIS IS YOUR BABY!!!
Here is a bit about why I am going to say what I am going to say (Sorry this is long)
I am the mom of 3 girls - and have had 3 losses. Of my 3 girls - 2 were preemies the first one was 4wks early and I was in the hospital 6wks for preterm labor. The 2nd one was 6wks early and I was in the hospital for 6wks for preterm labor and at home on FULL Bedrest for 3months (I couldn't stand the hospital anymore). So I can understand your fears/apprehensions/etc... She is your miracle baby (thats what I call my two girls). In addition to that I am also the daughter of a Pedi and my children's pedi and he also has given the 6month "rule".
BUT I didn't listen to him b/c I took the lead from my child (which he says as a Grandfather to do lol - he also says the Pedi can be an idiot - he can be funny). Which as Moms we know our kids best.
Anyway, what I am saying is talk to the Dr. and see what his/her reasoning is for the 6mo rule for solids. Is he going by the new standards? Is that just his thing? Is there a medical reason for your daughter to wait? I will say this my last daughter was in the NICU for a week after birth and on an apnea monitor for 6months (what a PITA that was) due to having SEVERE Reflux. Because of that I watched what I ate and what I would feed her when I started solids (at 4//5 months - she was a PIGGIE). I started he VERY VERY Slowly and explained to people that b/c of her reflux WE (Daddy/I) MUST APPROVE ALL FOODS!!! She was on 3 different meds for her reflux and so I watched what I gave her. She was on a modified BRAT diet for 3months with Solids. Let me tell you if I had waited for the 6mo with her she would have had a boob or bottle in her mouth 24/7 LOL
With all that said - I have gone along with alot of what my Dad has said and there are things that I don't do - I know my kids and if they are ready for something we try it, if it works great if not we wait.
Basically, Talk to the Dr and then follow your gut. If she is hitting all her developmental marks that is great.