What are you investing for?
Only put inside a retirement account if you don't plan to touch it until age 60+. Given it is very early in your life and career (I'm assuming based on your internship), it's not as important to diversify at this time. Your best bet is to choose a broadly diversified fund (VTSAX is fine for total stock market). Over time, you can continue to add and then diversify into other areas (intl stocks, us bonds, intl bonds, etc).
Given that you mentioned you'd like to withdraw in 10 years, there are ways to do this if you invest in a Roth, but only up to the 10k that you put in (remember than the annual limit is 5.5k for 2015, so you'll have to split between 2015 and 2016). Search "withdraw early from Roth" online and you'll find a lot of specifics. It's very tax efficient, given VTSAX only has a little in dividends.
Investing carries risk, so there are no guarantees. The market could tank in 8 yrs, or it could double by the 10th year. Timing is very difficult, but the long time horizon is on your side.
Without more details, that's my best general advice