I have created my website about Culper precision. recently , I have changed the theme of website. due to these changings my website take time in loading that is sometime more irritating for me.
Have you checked the Cache status in Magento admin, may be its disabled, you can enable it from Magento Admin by going to System -> Cache Management -> Check the enable status.
See this
you can also change it from cli by command
php bin/magento cache:enable
I would like to suggest 10 steps to Speed up:
Step 0: System -> Cache Management -> Check the enable status.
Step 1: Optimize Server and System Requirements
Step 2: Update latest version of Magento 2
Step 3: Enable Varnish Cache
Step 4: Configure Memcached
Step 5: Enable Flat Categories and Products
Step 6: Optimize Javascript and CSS
Step 7: Setup Content Delivery Network
Step 10: Optimize Images
Hope that helps!