Both ideally but I think you have to look at your own ethnicity and your parents to be honest.
My parents--both of them are not really 'wrinkled'.
My dad lost some volume to his face as he aged and of course has some lines..and My Mother really the only thing that sucked for her was her neck once she got into her 60s I would say (reason why I keep a good neck job in mind as preventative if that starts to go in next few years--its better to get mild work done in 40s ad 50s then once you hit 60s because skin elasticity)
I think retinal is fantastic..I use it at night (peter thomas roth PM retinol) and i use vitamin C serum in day (Drunk Elephant)--i love both these products and find I never have to moisturize it hydrates the skin naturally...
I use Peter Thomas Roth Pumpkin Enzyme mask on/off bi weekly.
I just started a Silk Peel which is microdermabrasion and I am considering doing laser Genesis.
I think if you parents are very 'lined' do botox but I personally think unless you live in LA or Vegas somewhere with a lot of Sun yearly late 20s is not really necessary.
When people get botox--even when a faint line is already formed--the botox relaxes the line...so if you wait until you get the beginnings of lines the botox will make the lines go away...it would take YEARS for you to have lines so deep that botox would not make them go away.
I hope that makes sense...be cautious of the Doctors because a lot of them the younger you start the more money they make.
As for retinol--I think you can actually go in Sun while using it unless you are using prescription strength(that I am not sure about)--I am NOT even using prescription strength it's not really necessary...use the over counter ones if you are concerned.
here is a quote from an article in Allure
You Shouldn't Wear Retinoids During the Day Because They Increase Your Risk of Sunburn
Are you sitting down? "This is one of the biggest myths out there," says Sachs. It's true that retinoids break down in sunlight, which is why they are bottled in opaque packaging and are still best worn at night—to make sure they aren't rendered inactive. However, they do not make the skin more prone to sunburn. "This misconception came about because in some early studies, people described putting on a retinoid, walking into the sun, and immediately burning. But that redness is likely related to heat exposure," says Sachs. "Clinical studies have shown pretty definitively that retinoids do not lower the MED—or minimal erythemal dos—of human skin, which is the amount of UV light you can take before the skin burns."
http://www.allure.com/gallery/biggest-retinol-cream-myths