This is my second time filing but I’m under sixteen can I file through e-file

While there is no minimum age to file a tax return, there is one to efile it:

Per the IRS Modernized E-File Manual:

The following taxpayers are ineligible to sign individual income tax returns with an electronic signature using the Self-Select PIN:
• Primary taxpayers under age sixteen who have never filed; and 
• Secondary taxpayers under age sixteen who did not file the prior tax year. 

Age is determined as of Dec 31 of the tax year (so, 12/31/2018).

Age doesn't matter, for free filing. But you probably qualify for Free file based on income.

TurboTax also has another free product called the Free File Edition (not to be confused with the regular Free Edition).  It has free Federal preparation and free State preparation. There is no efiling fee. It is not available after October 15

The Free file Edition can handle a 1099-MISC.

The Free file Edition is more fully-featured than the regular Free Edition.  The Free File Edition can prepare Schedule A, C, D, E, and F that the Free Edition cannot. 

For Free File Edition a user needs to meet only ONE of these qualifications:

•      AGI of $34,000 or less
•      or active duty military (including Reservists and National Guard) with a military-issued W-2 and a 2018 AGI of $66,000 or less
•      or eligible for the Earned Income Credit (EIC aka EITC).

The FREE FILE Edition is located at:
https://turbotax.intuit.com/taxfreedom

How to switch and start over in Free file Edition
https://ttlc.intuit.com/questions/2026912-how-do-i-switch-to-turbotax-freedom-edition