I find myself at a standstill in my writing, and it seems the further I get into it, the more frequent these standstills become. I'm writing two separate stories and I keep wondering if I should combine them, but then I would have to change the point of view of the first story. It's also a mix of sci-fi and fantasy, but I think I should probably lean more towards one than the other to make the setting more concrete, but I can't make up my mind which one I should lean towards. In the second story, I'm trying to decide whether to start the character out as a teenager or as a child. Starting the story in her childhood would work better, but that's how I started the first story and I don't want them to have the same layout, you know? Ugh! Sometimes I wish I had a writing coach or someone to talk these things out to! lol Am I just over-thinking all of these things, or does anyone else have trouble with making decisions in their writing, too?
It's always tough for me to decide just when to start the story off. Usually, I struggle with the actual scene, but I can see you're struggling with the starting age of your character. My best advice would likely be to choose the most interesting scene for your character and storyline/plot, and then entwine the most interesting or appropriate and fitting age for that scenario. I usually try and construct the world and situation around my characters, but sometimes choosing the situation first can help you reflect on what character you see in that situation, age and personality wise.
Think of it this way, these are the kind of decisions that you can change your mind about at any time. You're the writer. If something doesn't work, you can try something else, no pressure. Go with your gut. Good luck
as for where you should start the story, one good advice I keep hearing over and over is to start with change! start with the event that changes everything, the first day that is different. The event that leads up to the entire story. It might sound too general, and I don't know if it fits EVERY story, but it's a good thing to keep in mind. Even if the characters childhood has importance for the plot it's not necessary to start the story from there, it would probably be more effective to weave in parts of so called backstory-information in the actual story. Another advice is not to use x number of pages/chapters to warm up, but start when something actually happens. As for if you should combine the two stories in one, my advice is to write each of them separately first, and when you have a first draft of both of them you can decide on this.