It's never too early for prenatals. They do wonderful things for your body whether you're pregnant or not. Also, you could limit things in your diet that you need to when pregnant. Like caffeine, excessive fats and sugar, etc. Starting healthy habits now will create a much friendlier environment for babies to grow

And this isn't what you asked about, but one thing I did to prepare for the baby is to look on the clearance racks for baby clothes that are gender neutral and not season specific. I did that for 3 years before we had a baby and I ended up spending maybe $100 and had an awesome wardrobe started. Even though I'm sure you'll have a ton of people buying things for the baby when you do become pregnant, and you'll go shopping big time also when that time comes, it's really fun to buy tiny baby things even when you aren't pregnant
Good luck to you in the next year!