Doesn't look like anyone here has taken that track. At my store, we have had several go from Tm to ETL.
One I worked with was placed at a store about 1 1/4 hours away. She worked there for over a year, but ended up leaving because she was having a tough time with her mgt team. She was the a store mgr for a smaller mall store. Now, she is basically a gstl for a grocery store. She likes being done when she punches out--she's not salary and prefers it. I think she wanted the title and raise, not so much the job.
Another who went through the process was placed as an ETL after the internship. He thrived and was promoted to STL within a few years.
Lastly, we had an intern who still had a year of school to complete after the internship. Back then, there wasn't extended internship and she had to stay on as a tl. She was an STL and then dtl in short order. She was candid in saying that if she hadn't been a tl, she never would have made it. She was not an internal, but I think her experience illustrates how important that year after the internship can be. You will already be offered the job, so use that time to really decide if that's what you want. I'm not sure what your position is now, but as an extended intern, tell them you want to have keys and an area so you can get a good idea of what is coming.
More will be expected of you than non internals, but you will definitely get more out of it as well. I know that you are set to be at your own store. They do swaps with other interns too. Try to do at least one of those. It would be beneficial to see how other stores work.
Good luck, and have fun with it.