I think it does sound like fairly reasonable pricing for what it is, though it's about the same price, slightly more expensive for 20GB than it was for my dropbox account, which I stored everything on my computer on while I was changing my hard-drive. I don't really know much about this stuff though to be honest, and you've been giving me a free service for at least a year now.
One thing I will say is you're making a lot of changes to the site. It looks almost like most aspects of the site are completely being changed and you'll pretty much have a new site. Now I'm sure you're keen to let your investment pay off and start actually making profit on it, which don't worry, you will, but personally though I'm absolutely happy to pay for the service you're providing me in the future, I'd also like to experience the new site for longer than a month before I start paying. Let's face it, chances are in those first few months there'll be a whole load more changes you'll have to make, things that don't actually work, things that need to be tweaked etc. This is just narrowing down the problems. I just recommend you put the new version of the site in a beta period for a certain amount of time, like you did with the original, allow some more models to try it out, allow the ones who have been using the current site to see what they think of the new site.
I'm sure if you work on it that you'll be able to fix most things within a fairly short period of time, but I'd just not jump the gun by saying "you're all going to have to pay after x amount of time" before you absolutely know that the site is running completely smoothly and has no issues. If you turn around and say to your current consumers "we're totally changing the site you're used to and in one month you're going to have to pay for it." and the site has a whole bunch of problems, it may deter models already using the site, and likewise, if you say to new models that they have to pay immediately, and the site is still having issues and running through changes, it may deter them or make them angry at the site that they're paying for a service.
Just allow the models some time to adjust to all the changes before giving them a date that you'll start charging. We are a distrusting bunch of people, we also put a lot of risks into our jobs and any expenses eat into our income, also remember that the majority of camgirls are not well off and live paycheque to paycheque or just cam as an extra form of income. They possibly don't even sell that many videos, even if they have a lot on offer. I have used the current site since you first told us about it on here, I love it and trust the system, but I haven't used this new version yet, so in many ways that trust needs to be built back up.
You've always been incredibly professional, you've never been anything other than respectful towards models and our line of work. There are a lot of dicks out there who are looking to get a way into model's income, or wanting to find out all their personal details, I do not believe you're one of those people, you've never given off any of those vibes, but I am still wary as always. Other models will be too. You need to make sure that everyone knows that what they're getting is worth the risk of releasing their info.