Wow! Great for you at 19 years old and starting to invest in real estate. I started when I was 24 and still wish I had started younger.
In my opinion it really all depends on what you want to do. The fact it's a cash deal won't play much of a part in your decision on what real estate venture you choose. Cash is just always better when dealing with a closing and sellers prefer cash deals more so then mortgages. It's always best to buy with cash if you can. I have one mortgage on my first home from when I was 26 the others I always bought in cash.
Renting: Are you willing and able to be a landlord? When buying a home you become a business owner, it's just like buying into a business. You run and operate your property exactly how you would a business. There is a ton of responsibility with renting. For example, Can you make it to the property if a pipe burst at 2am in the morning? Also, Constant maintenance and up keep is required. I go by my properties on a weekly basis to make sure everything is running smoothly. Are you prepared to deal with tenants and all the issues that come along with them living on your property? These are some things to consider. But on the flip side, I love it! I have great tenants, I have a good amount of monthly income that covers all mortgages and leaves me with money for incidentals and profit.
Flipping is also a great way to make money, but you can lose it just as quick as you can make it. A lot of people have this misconception that you buy a property, fix it up, sell it and BAM your rich. Not the case at all, at least when I started out flipping. I had to go broke and had a lot of debt on my first one, you have to be prepared to have money for all types of rehab issues on the property. Contractors, sub contractors, permits, licenses, RE agents, etc are very time and money consuming. Always, for some reason after a couple weeks something always goes wrong and something needs to be re-wired or a wall needs demo b/c of an old pipe that has a slow leak when you turned the water on. Also, IMPORTANT know the market that's probably the most crucial aspect when flipping. I check the market on areas daily, I research any new developments in the future or pay attention to crime rates and neighbors, etc. If you don't do your homework on comps that compare to YOUR home not comps of the general area and homes that are not similar to yours you can fall short of any profit.
It's a gamble, but an exciting one. I love to micromanage and rebuild the home and change layouts and pick out granite and design the bathrooms, etc. it's a rush for me.
You can do very well for yourself flipping as long as you do the research, I did and still do to this day spend hours sometimes researching areas that I potentially want to buy in. Just don't jump in blind or you can end up in a mess. What it all boils down to is what you are ready for and what you can handle. I started out first renting. I'm very happy I did it this way,because I was able to learn along the way such things like tenant landlord rights, building rules and regs, comps, and all aspects at a slow rate. When you flip you have to be ready to move quick. You have a time frame and it's not long, you want to sell as quick as you can and role that money over into another investment. But good luck, and this is just my own experiences and opinions. But it's very exciting and wouldn't change what info for any other job!! :)