Lissa just got killed by Marth. Do I chalk it up to experience and restart, or should I press on? In general, I'm not great at SRPGs, and I'm afraid this will make the game impossible for me.

Personally I never used Lissa on any of my 4 playthroughs. You should be fine if you press on. Really up to you how you play if you wan't to keep deaths permanent with no restart. If it's your first playthrough, and you are new to the series just restart, and enjoy yourself without the perma death.

It depends on how much you care about missing characters. If the ones essential to the plot die you'll game over, but a lot of the fun of the game (at least for me) was the support conversations, and if you're into those and want to see how Lissa interacts with the others you might want to keep her around. Strategically, though, you'll get two more healers pretty soon, and even if they die there's the Spotpass stuff that lets you recruit characters from the old FE games to keep you together, so Lissa isn't essential. Maybe save this run to another file slot? I let three people die early on when I played through and I ended up just restarting whenever anyone else died afterward, but if you're super into the permadeath aspect and don't care about Lissa as a character, you don't need her strategically.

I stopped using Lissa pretty quickly so you will be fine to keep going, but you might have difficulty if you don't have any other healers yet. You are still early in the game so restart if you want.

I never used her. You get better healers eventually.

I never finished that game because I'd constantly restart battles when I'd lose characters, so I encourage you to just keep trucking. You're also pretty early on so you'd probably be okay with restarting if it eats you up inside. You monster.

Depends on how OCD you are about keeping characters alive. You get Mirabelle, who is arguably a better healer because she's mounted, pretty soon anyways.

Thanks for the great feedback everyone. I think I'll move this one to a different slot and start again. It's hard to say if I'm going to care about Lissa's interactions with the other characters at this point, but I'd hate to get another 10 hours in and decide I do.

Yeah, once I got to upgrade Miriel to Sage I largely stopped caring about including other healers except Maribelle occasionally. Didn't stop me from constantly restarting to get through levels with little to no allied deaths though, so take that with a grain of salt.