As the comment from #closetnoc indicated, the sitemap is really a reference point only. The Google bot will crawl your site, so the best thing you can do to speed up the process is to ensure that there are no blocks on indexing in your robot.txt or site settings, and ensure your site's navigation links provide a path to all relevant pages, and you have a few internal links to other internal pages from each page to keep the bot going. Use Search Console to test these things.
To index a lot of pages will take time, since the bot follows paths and isn't going to get every path first time, but your site doesn't have to be ages old before a lot of it will be linked. While the sitemap can help, for deep pages, Google tends to prefer those pages which are hyperlinked from multiple sources (ie. hence the importance of internal linking).
Sidenote: If your site is created using a CMS, as Google starts indexing your site, you might want to check that you are not getting multiple links for the same page, particularly if you are using many different categories. https://joomla.stackexchange.com/questions/10046/how-can-i-get-rid-of-category-pages-in-joomla/14557#14557