Should I tell my parents I am agnostic?

(Guess I'm not really quitting?? Looks like I still have a lot of sentiments I need to express. I've decided that I'll only journal when I want to, and that I'll only make them public if they can help others.)

I was around eleven years old when I first started questioning and doubting the beliefs instilled into me about God. This journal entry is not about the reason why I am agnostic; rather, it is about the state of my mental health after hiding this information from my parents for so long.

With that being said, how am I? I would like to think I am in the best place I have ever been in my entire life because of what happened last January when I finally started taking control over my life and living how I wanted to. However, I am still not in my theoretical best place because there is still one important aspect of my life I would like to change, religion.

I am debating with myself whether or not I should tell my parents I am agnostic tomorrow - tomorrow also happens to be my birthday. (Wooo, I did not plan for that :P.) Here are the reasons for why I maybe should not tell them:

1. My parents are religious, but not overly. They still make all of my siblings and I go to online mass every week, but other than that, they barely talk about religion. I know my mom is religious, but my dad might not be since he frequently sleeps during online mass.
2. I hate how there is a high chance I will heavily damage my relationship with my parents because I really love them. I do not say this for them or their state of mind. I say this for the close relationship we have that I deeply cherish - two very different things. I am currently on very good terms with them, and I would like to think both of them are proud of me. How negatively would telling the truth affect the family dynamic if it did? I honestly have no idea as to what their short-term reactions and long-term processing would be to me telling them.

Here are the reasons for why I maybe should tell them:

1. Carrying this burden for years and years can be really damaging to the mental health of a person, and I understand this. I am glad I sought out the truth at an early age and started thinking about these things early on; however, because I was so young, even after so many years of thinking about these concepts, I am still quite young which means my initial plan of waiting until I am older and independent would not happen for a very, very long time. I am nearing my breaking point, so I would like to stop living a lie.
2. I actually think the probability of them not financially supporting me anymore for me not being a Catholic is pretty much zero because 1.) I know them, and they do not seem like the type of people to do that, and 2.) they still financially support my older brother even though he dropped-out and is just staying at home. (That is something I need to journal about and talk to him personally about...)
3. If all works out, I will not have to go to weekly mass or any religious events anymore which means I will have more time to do the things that actually have meaning to me.

There is also the question of "Should I change schools?" if I do decide to say I am agnostic because I am currently enrolled in a Catholic school. Sadly, I do not think I should because: 1.) I have been in my current school since kinder, and I have made so many great friends along the way. 2.) Most "good" schools in the Philippines are Catholic because almost 90% of Filipinos are Catholic. And, 3.) It just seems very complicated and unfeasible to do so.

After reading through the whole journal entry, the prospect of telling them now does not seem too bad actually; however, I am still in the process of figuring how and when to tell them. Plus, there are still questions like: Is it a good idea to tell them on my birthday? Is it a bad idea to tell them during Christmas? With all the context I have given, should I tell them or not?

Hopefully, those in similar circumstances who see this might somehow learn something from my journal entry. I am still very much troubled about this, so I would appreciate any comment. Be kind and keep striving!