Like most things, Line type is pretty simple. A double taper is exactly that. It starts out thin and gets fatter toward the middle with a constant matching taper to the opposite end. Many people just flip the line when one end gets worn. A weight forward line has a similar taper to a double taper only more pronounced than a double taper. It then has a very sharp taper to a long section of non tapered or flat line. The weight forward allows an experienced caster to cast further and heavier flies than a double taper, but lacks a bit of delicate presentation. I use only weight forward for bass and panfish because I usually cast bigger more wind resistant poppers and flies than I would for trout. As for rods, I used a fiberglass Fenwick #7 rod for years before I graduated from college, because I got it used at age 13 and that was all I could afford. I caught 6 inch trout to a couple of large sharks with it. That whole time, I wanted a #9 rod to cast big bass plugs better. When I got the #9, it was a clunker, (also fiberglass Fenwick) but did the job. I now have a carbon fiber #8 and love it for everything but finicky trout (#5) and bill fish (#12). Use what you have. When you feel you have outgrown the rod, go to a good fly shop. They will let you test different rods if they have their act together.
Note: I doubt you will ever get good or be happy trying to cast large poppers and saltwater size streamers with a #5 rod. Get good with the lighter flies then move up, or pick up a #8 carbon or #9 fiberglass cheap at a yard or estate sale for the big stuff. When you have mastered both the 5 and 9, you are ready to invest in a higher budget rod for more than just the prestiges name on it. Most important, have fun. Trust me, it is a better feeling getting skunked practicing in the back yard than fishing on the water.

Most of the big bass I have caught with a fly rod were on a number 8 rod. Most were caught within 30 feet. Panfish are often caught within two rod lengths. As for flies, even though considered by some outdated and replaced by a wooly bugger by others , a black with red tail and grizzly hackle still outperforms most flies for me on big bluegill. I usually cast out , let As for trout, including stocked trout, I have converted to olive body black tail wooly bugger with with black hackle. My Bluegill popper favorite is a 1/2 inch body black with red face, yellow split hackle tail and rubber legs. I catch more bluegill on a smaller popper, but bigger bluegill with the bigger popper. The bigger popper also has produced some big bass while panfish fishing. These are my favorites, but do not be afraid to change up. even bluegill can have different moods on different days. Note if you want a lot of practice and don't care about size, an ant pattern will likely get you the most action and the most experience with setting on strikes. Again, I have caught more than my share of bluegill within a rod length or two of the rod. Good luck

Most of the big bass I have caught with a fly rod were on a number 8 rod. Most were caught within 30 feet. Panfish are often caught within two rod lengths. As for flies, even though considered by some outdated and replaced by a wooly bugger by others , a black with red tail and grizzly hackle still outperforms most flies for me on big bluegill. I usually cast out , let As for trout, including stocked trout, I have converted to olive body black tail wooly bugger with with black hackle. My Bluegill popper favorite is a 1/2 inch body black with red face, yellow split hackle tail and rubber legs. I catch more bluegill on a smaller popper, but bigger bluegill with the bigger popper. The bigger popper also has produced some big bass while panfish fishing. These are my favorites, but do not be afraid to change up. even bluegill can have different moods on different days. Note if you want a lot of practice and don't care about size, an ant pattern will likely get you the most action and the most experience with setting on strikes. Again, I have caught more than my share of bluegill within a rod length or two of the rod. Good luck