No, lower weight less reps is not the way. Building muscle is fine. You can't build too much muscle on a Women anyway.
If a Woman was using serious amounts of Anabolics, then yes Women can get for example a 17" arm measurement, with probably less than 20% bf. I've seen pics of a Romanian woman, claimed to have such a measurement, though the way she portrays herself image wise, doesn't appeal to me, though I must respect the hard work put into such a body.
That would be an upper limit for female muscle building.
The reality is, unless you were on about 200g Protein a day, then for you to get "Natural" Arm measurements, of around the 13" mark, which is perfectly doable, would be nigh on impossible, because a Womens ability to build like men, is greatly hindered by their significantly lower Testosterone levels.
Muscle building has good benefits, which you will be greatful for when you're old, especially after the age of 50, when muscle and Bone density decline, can be a really strong factor, and if you're someone built like a Marathon runner, and also training with low weight high rep strategies from the get go, by the time you're 70, you could be little stronger, and little physically improved, over that of Ectomorphic women, with sub 1,500 calorie diets, and a sedentary history.
If you want to see what a good strong body looks like, you could check out the site for a Canadian athlete called "Allison Ethier", who just competed again, and won again last month.
Her site has links to recent contest pics.
Also Bodytrimmer A.K.A Bridgette Rhea, who contributed occasionally on my site, can be found by putting her name in Google in quotes, and finding pics of her on the Google image finder.
Both are totally natural, both have competed, and probably compete with about 11.5"-12" cut Biceps.
I'm not saying you should necessarily compete, or go totally for that look, but such excellent female physiques, highlight the benefits of lean, strong and healthy femininity, with lasting results, because the right approach is used, so they almost certainly WILL, still be very healthy and physically conditioned people by their 70's .
Both are very good looking, and to my mind rolemodel material for other females, including under 21's, hence why I chose those two names in particular.
I'm not totally convinced about the 1,450 calorie level, but I do believe the schedule you're being given will make a difference, and is doing so, so you should perhaps stick with it, and see what happens.
You should still be very proud of what you've done, as good advice makes good results feasible, but hard work makes them happen, and you put in the effort, and get out what you put in, so you deserve to be proud of that