I own an R3 and a P2C and I like them. When I bought mine, I was custom fitted by the LBS and looked a different bikes and test rode several. I decided on the R3. We took the Cervelo R3 as shipped by Cervelo and stripped the components and wheels. I put a partial D/A gruppo which included Brifters, brake caliper, front and rear der and chain. I put on an IRD carbon crank, carbon bars and a carbon stem. I had my own wheels and cassette. The frame is ~$3000 plus other components and wheels.
Cervelo equips their R3 with some D/A equipment but you should check if it is all D/A. For example, it may have Cervelo brake calipers, a 105 cassette and chain and a different crank. Typically, the wheels are entry level. The Eastons are okay but heavy and worth a couple of hundred dollar credit if you upgrade.
Most of the Cervelos that sell from the LBS I use go from $5000 on up depending on the wheel selection and gruppo.
When I bought my Cervelo road and TT bikes, I wanted a bike that was tuned to ME. At that price point, it is all about me not the deal, the bike or the bike shop. $3700 is a great deal if it is all about YOU and what you want and need.
I cannot speak to the question of seat to bar drop. When I was fitted at the bike shop, my flexibility and goals were taken into account. It has nothing to do with age. You need to figure that out. Good luck.
