Yes I would definitely push the nap out and maybe bt too but would try the nap 1st if she goes down ok at bt. Personally we jumped from 12 to 1pm in one day and got quick results in a few days (5 to 6am), we do already have an 8 pm bt though. But maybe you should just swallow ot for a day or 2 not to be still tweaking in weeks. My ds 2 just won't do 12 hrs so maybe m is the same and 7 to 6.30 is too much to hope for. We have been doing 8pm to 6am (occasionally later) with 1.5hr nap at 1pm, although now we seem to be nap dropping but that worked for several months after months of 5 am wu ( torture). K who I think of as a good sleeper ( Sttn from 9mo and did 14 hrs nights when he nap dropped and still 12.5hr nights now at Nearly 4) did 1.5hr nap with 10 hr nights on one nap but it bothered me less because I did 9 pm bt ( had a naughty b up anyway at that stage so no me time) and he was waking 7 or 7.30am.
Hope it helps. Whenever I look back at transitions I wish I jumped sooner to avoid all the torment.