Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Brooklyn Nelson
Table title:
Theatre credits
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Year </th><th colspan=1 rowspan=1 > Production </th><th colspan=1 rowspan=1 > Role </th><th colspan=1 rowspan=1 > Venue </th></tr>
<tr> <td colspan=1 rowspan=1 > 2015–17 </td><td colspan=1 rowspan=1 > Matilda </td><td colspan=1 rowspan=1 > Amanda Thripp + swing </td><td colspan=1 rowspan=1 > Shubert Theatre </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 2017 </td><td class="highlighted"  colspan=1 rowspan=1 > Frozen </td><td class="highlighted"  colspan=1 rowspan=1 > Young Elsa </td><td class="highlighted"  colspan=1 rowspan=1 > Buell Theatre (Denver, Pre-Broadway Tryout) </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 2018 </td><td class="highlighted"  colspan=1 rowspan=1 > Frozen </td><td class="highlighted"  colspan=1 rowspan=1 > Young Elsa </td><td colspan=1 rowspan=1 > St. James Theatre </td></tr>
</table>
Question:
When did Brooklyn Nelson play the role of Young Elsa?
Answer:
Brooklyn Nelson played the role of Young Elsa in Frozen, first in the Denver tryout in 2017 and then in 2018.