Great start!
I am not feeling the second shot due to the softbox being the background there. My suggestion there is to watch the background, it can make or break a portraiture style photo.
The first shot is much better for me, and I will add a few points to help in the future:
- Look at the catchlights in her eyes, it appears there might be a window off to one side and the lights on the other?
- The light might be a bit too close or too direct in this shot due to the bright highlights on the left brow.
- You might experiment with shooting wider and cropping later perhaps, unless that is what you did here. It adds the ability for you to fine tune the final result that way. I always make the mistake of shooting too tightly and kick myself all the time afterwards. 
Detail is very good, and colors look good as well, both can be managed during post processing too.
Don't get hung up that you are using a rebel or that you are using a kit lens or that you have a crop sensor, they are perfectly fine. In fact I still keep the 18-55 STM lens around for group shots, as it can be a good portrait or group lens in its own right. Also a crop sensor gives up nothing to a FF sensor in the cases of set up studio style shots, you are going to always set up whatever aperture for the DOF you want, and you will likely be at a low ISO, so FF doesn't have much gain over a crop body in these situations IMO.
I assume the lights you got were continuous lights? I started with those and after a year or two, I got rid of them. When you get to the point of wanting to use strobes or flashes, take a look at the Godox/Flashpoint line, very robust systems for very little money. It looks like you are willing to really dig into this and try new things, so this is a great first round, keep up the creative uses of the lights and see what kind of look you like.
Look at the XproC for the transmitter, and then their TT flash line or AD strobe line.
Having strobes/flashes allow you more room for studio style portraiture, like using a black background or control how bright your fill lights are for the shadow areas, something that is much more difficult with a continuous light, I feel.