Thats a hard question to answer. The overall process took a ton of planning and pulled from alot of areas that i have done some work before. If you are familiar with framing, some cement and tile work, i say go for it. Prepare for mistakes amd take your time. The shower pan was more difficult than i thought. It was my first one and i would say it was the hardest part. Getting the angles right to flow water into the drain was tedious. Id say watch some youtube videos on that part for sure and shower waterproofing. This took me about 14 days all together.
Anytime. Another option for the shower pan would be a pre-made fiberglass one. They come in a variety of sizes, but the large ones can get expensive. Good luck and share your build!