When I first started I was in your same position. Training with experienced grapplers can be off putting and painful, but dont let it get the best of you. Learn from the mistakes you make and try to replicate what they did. A few things you can do from home:
- Yoga/Core Exercises: Seriously important. Your core is one of your biggest weapons in BJJ. If you have a great core you'll be extremely hard to grapple against. I use Yoga and a few other exercises to work my core like light weight lifting (don't try to get buff, try to get lean) and a few other things.
- Learn Anatomy!: I know it's high school science all over again, but knowing the human anatomy is something that proves itsself extremely useful in grappling. Think of it this way, if you're stuck in a bad spot but you don't know a submission/sweep to get out, think of the bodies weaknesses and exploit the nearest one. For instance in one of my grappling sessions I was in an armbar by a guy who outweighed me by about 60 lbs, and it was deep. He made the mistake (some people do it anyways, but I don't solely for this reason) of crossing his feet next to my head. He had my arm fully stretched, outmuscled me and there was no way I was slamming him. So using my knowledge of anatomy, I realised I could ankle lock him from that position due to his feet being crossed by pressing one ankle down on top t he other and stretching the tendons in his foot. He tapped when he had me in a deep armbar
- I know Slidey says video's aren't the best but they definately help. Look up some things and practice them, but dont forget to talk to the instructor about them later to ensure you aren't making mistakes.
- Practice with a friend from class, or even a wrestler from school. Wrestlers are really good to practice sweeps on since they're usually used to defending them.