Observing commandments prior to official conversion

Is it possible/allowed to practice Judaism without officially converting? I am only sixteen so I’m still in school and live with my Christian parents, so I don’t have the time, money, or resources to officially convert at this time. May I begin to practice Judaism and officially convert at a better time in life, like when I’m an adult, or should I just wait?

It is permitted to observe all commandments before you officially convert. The only exception is keeping shabbat. A Non-Jew is forbidden to observe it.

However, it is only forbidden to observe it in its entirety. Before you convert, you may avoid violating all of its prohibition except one. For example, it is sufficient to light a fire once at some point during the shabbat.

The reason for this is that shabbat symbolises the covenant between God and the Jewish people. The verse in  Shemot  31:13 says: 'You must keep My sabbaths, for this is a sign between Me and you throughout the generations, that you may know that I God have consecrated you'.

It is written further ( Shemot  31:17): 'It shall be a sign for all time between Me and the children of Israel'.

For this reason it is prohibited for someone who does not belong to the Jewish people to interfere in this relationship.

Sanhedrin  58b