Well, let’s see if we can break this down.
First, there are four (4) Marian dogmas: 1. Ever Virgin; 2. Mother of God; 3.Immaculately conceived; and 4. Assumed into heaven.
Second, in order to enter the Church you need to “HONESTLY” be able to profess the tenants of our faith which are:
I believe in one God, the Father almighty,
maker of heaven and earth,
of all things visible and invisible.
I believe in one Lord Jesus Christ,
the Only Begotten Son of God,
born of the Father before all ages.
God from God, Light from Light,
true God from true God,
begotten, not made, consubstantial
with the Father;
Through him all things were made.
For us men and for our salvation
he came down from heaven,
and by the Holy Spirit was incarnate
of the Virgin Mary, and became man.
For our sake he was crucified
under Pontius Pilate,
he suffered death and was buried,
and rose again on the third day
in accordance with the Scriptures.
He ascended into heaven
and is seated at the right hand of the Father.
He will come again in glory
to judge the living and the dead
and his kingdom will have no end.
I believe in the Holy Spirit,
the Lord, the giver of life,
who proceeds from the Father and the Son,
who with the Father and the Son
is adored and glorified,
who has spoken through the prophets.
I believe in one, holy, catholic,
and apostolic Church.
I confess one baptism for the forgiveness of sins
and I look forward to the resurrection
of the dead and the life of the world to come.
Arguably, only “mother of God” and “ever virgin” are contained in the profession of faith. So “arguably” you could honestly say the profession of faith even if you are still struggling with the Immaculate Conception and the Assumption.
Catholics are required to accept all dogma with “assent of mind and faith”.
So . . . assuming that the Immaculate Conception and the Assumption are the only two Marian dogma with which you struggle with AND assuming that although you might not fully understand them but can at least give intellectual and spiritual “consent” to them, i.e. don’t “object” to them, I would say you “can” become Catholic. But in so doing, and frankly this applies to ALL Catholics, you need to continue to make efforts to “form your conscience” according to the teaching of the church, which for some of us will be a lifelong process.
As an aside, and this may more appropriately address your concern, it is possible to be a good Catholic in full communion with the church and have NO devotional practice focused on Mary. No one is “required” to pray to Mary, to ask Mary to intercede for them, or even to keep Mary mentally in the front of your prayer life.
As a second aside, my sister in law was raised Wisconsin Synod Lutheran. She had significant issues with all our “Marion stuff”. She and my brother in law, a cradle Catholic, were married in a Lutheran Church (he had a dispensation). She had no intention of converting but attended RCIA in an effort to learn more about Catholicism. The priest told the class (somewhat inaccurately) that if they could say the creed honestly, they could become Catholic, so she did, without accepting the Marion stuff. Now she prays the rosary every day.