i too am a newbie and I wanted to say hi and welcome!

My advice would be to ignore the seat on the bike because bike saddles are so easy to switch. Often you have to try a few to find a comfy saddle. Some stores have this gel that you sit on and it tells you how wide your sit bones are inside. I changed my saddle to an inexpensive one because it felt the best and it made a huge difference. It was $20 something.

You also really need padded shorts. Before you buy them make sure the chamois is thick enough. You can buy the kind that you wear under any clothes or the spandex shorts/tights. Other than padded gloves and a helmut and water bottle that's all I started with. I added a little thing that keeps track of miles and speed and I like it.

The mistakes I made... I bought a bike pack but it's not big enough. My husband's is bigger, why would I think I needed a tiny one?? You hook it on the back of your seat and carry an ID, cash, kleenex, energy food etc in it.

About bikes. I have a road bike and I like that I can change hand positions. With a mountain bike you can't do that. I didn't upgrade to the shoes that go into the special pedals yet. My bike came with toe clips. They take me a bit to get my feet into when I start but they are ok. I just wear stiff walking shoes with them.

Good luck!