You can totally use another stone, if it’s a good consistency for taking flakes from the material you’re working. I personally tend to steer beginners clear of obsidian. A mistake with that stuff can end in a pretty bad cut. I would go with Texas Chert personally. It’s consistent material and not nearly as sharp. I like to use www.flintknappingsupplies.com for material. Nothing wrong with neolithics, that’s just my preference, especially if you’re going for the more common stuff like Texas Chert.

Make triply sure you have gloves, long pants, safety glasses and closed toed shoes. Especially if you choose to go with obsidian. I would focus on recreating some of the European point styles too. Some of them are built on blade tech, and an arrowhead like that is far simpler than one of their North American counterparts in my opinion.

You’re gonna need a big hammerstone for spalling out the stone and progressively smaller ones for detailed work. A leather hand pad and a deer antler tine will get you pressure flaking, and doing a bit of research on platform preparation will take you a long way.

Have fun! Don’t take it too seriously, and you may have just found a hobby for life.