How long does it take for 20-minute daily meditation to start showing benefits in everyday life?

that shouldn’t be your worry
if you meditate without hurry to see if its working
expect a year or more to see the effects
meditation = persistent = willpower
if you start doing meditation don’t give up
’cause if you do you’re weak

say this before your next meditation:
Say this prayer out loud:
“Lord Jesus, I believe You are the Son of God. Thank You for dying on the cross for my sins. Please forgive my sins and give me the gift of eternal life. I ask You in to my life and heart to be my Lord and Savior. I want to serve You always.” Amen

Meditation is not a quick-fix. The results are gradual, but if you keep at it, you will begin to notice changes. I have been practising meditation for 15 years now, and I still find there are days when I just can’t keep my attention with the present moment. However, I can look back and see profound changes in who I am and how I behave. I am kinder, more accepting of people and events, and less susceptible to negativity. I think of meditation as training – sometimes hard, sometimes boring, sometimes magical, but always valuable. Persistence and consistency are important – better to sit 20 minutes a day than for an hour every now and then.
Stick with it, and I wish you well.