Maybe learn more about investing while you continue to contribute to your Betterment accounts. Just by doing that you're ahead of 90% of people. Betterment charges higher fees than Vanguard, which over the long run will lower your return appreciably. But it will have little effect in the short term, and Betterment's fees are still lower than most mutual funds. It's not the emergency some on here are making it out to be.
When you reach over $10,000 in your Betterment account, ditch Betterment and switch to Vanguard Admiral Shares. If you already have this much, first, congratulations, second, learn more and then switch (once you've learned enough, the reason for switching will be obvious). Or just keep Betterment if you're not willing to learn on your own--like I said, it still puts you in the 90th percentile just by opening and contributing to ANY investment account.