Stocks are too risky for a three year time horizon. You want intermediate municipal bonds or intermediate treasuries depending upon your specific tax situation (see the Morningstar tool for comparing post-tax yields).
The Schwab bond stocks have a very low Morningstar rating. The large cap funds have been doing so well year-after-year. Are they really that risky?
Not to offend, but this statement really shows how inexperienced of an investor you are.
Please seek to understand the difference between saving and investing. Investing is putting money toward building long-term wealth. Saving is putting money in a savings account/CD for something you'll need in <5 years.
Another way to think of it would be to think about how much $ you would be willing to "lose" if the market were to turn south right around when you needed your money to buy a home. Let's say you think $10k is an amount you'd be willing to lose and wait to make up if that happened by saving for a few more months. Since a 30% market drop isn't out of the ordinary in a recession, then you'd probably not want to invest more than ~$13k by the end of your third year.
If you have 13k invested and 87k cash, then if the amount invested went down by our 30% example, you'd need to make up another ~4k in savings to meet your 100k goal.
You can adjust for what you feel is reasonable risk. However, honestly, and I'm trying to be constructive by saying this, you really do need to do a lot more homework on investments and the whole investing world before just blindly buying things through your Schwab account because they "...have been doing well year after year".