1st Fly Rod, where to start
If you think you're only ever going to buy 1 rod, and reel get a 8wt; if you tie into something big, and fast accidentally you'll be less likely to loose tippets, and leaders.
Not crapping on the big box stores, but you get what you pay for. What I mean by that is if you purchase from a Fly Shop you also get the knowledge of the shop as well. If you look strictly at the components (rod, reel, line, leaders, ect) you can most likely do better price wise at a big box store than at a fly shop (not always the case). But if you do purchase from a fly shop they are incentivized to help you, give you guidance and expertise that will be rare to find at a big box store.
Not sure where you are located, but if you are near Milwaukee go visit The Fly Fishers (96th and Greenfield). Full disclosure and many on here know, I am closely associated with them, that is how I know they are good.
Both Pat and Jared (Father / Son) are experienced professionals that not only know their stuff, but like to help educate those that are new to or expanding their own experiences.
They carry both Echo and Reddington products which are very good quality and reasonable priced. They are very well equipped to put together a combo for you that will fitted best planned on the intended use.
Whatever you decide to do, best of luck, and most of all have fun.
The Crosswater combos were good starter setups for me but I go cheaper for the 8wt rods now because I'm rough on them in the tribs. The Crosswater rods have worked great with for my 5wt setups, though. Line makes a difference with casting, I upgraded but you don't have to. Play around and see first. You can find some steals on line if you look around, same for the rods and reels. I keep spare spools for each reel loaded with different types of line (sinking, etc) in case I want to switch things up. It's easy to start out with a basic starter setup and upgrade components as you go. I'm still an amateur by far but you can learn a lot by playing around. I'd also look around in your area to see if there is a flytying or flyfishing club. That helped me a lot and I make some friends in the process.