You will get lots of opinions, some quite passionately endorsing o/c or ccr. I don't know that there is any one right answer for everyone. First off I would say that at less than 100 dives the first thing you need is more experience. I am not trying to slam you but 100 dives is drop in the bucket when you move into the technical world and the experience you gain just at the recreational level will carry forward with you.
From there I would suggest a AN/DP (advance nitrox/deco procedures) class. This is traditionally done in doubles with a single gas for decompression. It will teach you many of the skills that you will need in the technical world, both o/c and ccr. There are IMHO several advantages to this. One...it's a much cheaper investment to find out if technical diving is really for you. I have seen divers set up doubles, take the first class and on their first dive to 150 feet decide it wasn't for them. The regulators you acquire will transfer to bailout regs when you go to ccr. The deco bottles will become bailout bottles and the doubles you can either break up and use for bailouts (if they are aluminum) or sold to help fund the ccr. The gas switching skills, decompressions skills, stop holding skills, etc is all stuff you will need for ccr anyway.
After that, if you still feel you have the desire, the hunger to pursue a rebreather go for it. It is a commitment! It is not the single tank lifestyle where you can throw your gear in the closet for months at a time and just pull it out and go diving. Rebreather diving requires that your head be in the game at all times. It requires frequent diving and practicing of skills, however mundane they may seem. It requires more time in maintenance of gear, and more time in set up for each dive. It is expensive. The dollars you save in gas is quickly out weighed by the other equipment, computers, bailouts, etc you seem to always need.
All of that said, the rebreather is a wonderful piece of equipment particularly well suited for deeper dives or longer penetration runs. I have been on a rebreather for several years now. I did what i described above and think it was the best route for me and think it is a a reasonable approach for most divers who wish to go ccr. I had hundreds of o/c doves and then took AN/DP/helitrox. This got me to wrecks in the 150ft range with a single gas for decompression. It only required a set of aluminum 80's and a 40 for deco. Pretty cheap investment. I learned with tables. And after a short time in that level I knew I wanted to go full trimix and rebreather. There was no point, in my opinion, is doing that o/c. I made the move to a rebreather and pursued full mix and full cave on the ccr. The skill i learned in AN/DP were completely usable in ccr and layer the groundwork for an easy transition to ccr and bailout procedures.
Enjoy the journey.
