Hey!
I am a beginner, and I’ve come to the part where I am practicing my strumming patterns. In the video Justin used a pick, I myself find it easier without a pick. (Keep in mind my pick is still quite thin, meaning 0.71mm. ) Will it affect my journey negatively if I don’t use a pick?
Thank you in advance!
Hi Masa, welcome to the community !
It’s great that you are having success with the finger strumming, it’s a great skill to work on for sure. Additionally, I would advise not skipping practicing with a pick sometime too as it’s an important skill to have for the rest of the course. It’s worth it to persevere. 
No, plenty strummers don’t use a pick, and everyone has a different journey.
You will learn a lot without using a pick, so don’t let that hold back or frustrate your progress.
Don’t give up on the pick at this early stage. Keep it as part of your practise routine and it will come good in time.
Most of all, keep having fun … 
Welcome to the forum Masa
A 0.71mm pick isn’t a thin pick. It recommended to start with a 0.38 or 0.46 nylon pick.
I agree with Mathieu strumming with a pick is a skill you should have in your tool kit even if you plan on playing fingerstyle.
Some guitarists dont use a pick, some afik never have (Mary Spender etc?)
But dont choose not too because you dont have the skill. Using a pick is a skill like any other.
And there are a lot of things that are difficult or impossible to play without.
So stick with the pick, a thin one is good as its easier to use.
This for sure!
Much easier learning with a thin pick as we tend to grip the pick too firmly when starting out which makes it difficult to strum with control. As you become comfortable with your thin pick you will want to try firmer picks and will find them much easier to control.
Agree with what others have said about thin picks. I started with 0.46mm and now play 0.60mm. I’ve got some 0.73mms pick but they don’t feel the same at all. It may only be 0.13mm difference which is almost nothing but the 0.60mm one is noticeably more flexible than the 0.73 is. I can strum with the thicker pick but there’s definitely more resistance there
I’m like you and using my thumb or fingers and have done since I started the course 3 months ago. This is because I practice at night when everyone is in bed and it’s quieter but I do like to practice with a pick whenever possible I think it’s a skill to learn and I would like to be able to do it too
Hello and welcome to the Community Masa.
Justin covers this in a Grade 1 lesson
One thing I’ve noticed…people who don’t use picks tend to play very quietly …especially when self taught.
This is good when you don’t want to disturb people, but it’s …sometimes…bad when playing with other people, or for listeners.
It sounds like you are also practicing with a pick, but I would suggest that when not using a pick, that you practice playing at louder volumes as well as softer ones.
Welcome to the community Masa! I have done most of my playing without a pick, though mostly because of an injury that left my right index finger somewhat numb. I have recently started using a leather pick, as it is easier for me to hang onto and control.
Hello Masa, I’m primarily playing without a pick as I prefer feeling the strings with my fingers.
But I agree with others, that being able to play with a pick as well is a valuable skill.
That’s why I’m also doing particular strumming practices with a pick.
I wish you lots of fun along your guitar journey 
.