Happy Girl, Rav Noach Weinberg Zt’l told me many years ago that in considering both growth from where you are at and tshuva from where you have come to, every single mitzvah performed, has immense value, and no one should be discouraged by not taking on “everything at once”. The key is to keep going, but to do so realizing the importance of each mitzvah, even something as simple as putting up a mezuzah, or something more complex.
There’s also a thought in a midrash that may have been the earliest midrash I ever learned, maybe at the age of 4 or 5, which indicates (as an inspiration if not in actuality) that if one thinks about transgressing but doesn’t, no onesh applies. But if one intends to do a mitzvah but doesn’t, he receives schar as if he did it.