We are not able to tell you whether Allah will forgive 'you' specifically. Because it depends on whether or not you repent before your death, and on whether or not this repentance is sincere and adequate in the sight of Allah. You need to understand that only Allah knows the eventual fate of a person, and the people answering on this website are not Allah's prophets or messengers, nor do they have a way to gain the knowledge of the unseen.

Forgiveness after Repentance:

If a person truly repents then Allah can forgive him/her for doing X. Because X is included in the following verses:

قل يا عبادي الذين أسرفوا على أنفسهم لا تقنطوا من رحمة الله إن الله يغفر الذنوب جميعا إنه هو الغفور الرحيم

Say, "O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful."

^{— Quran 39:53}

ومن يعمل سوءا أو يظلم نفسه ثم يستغفر الله يجد الله غفورا رحيما

And whoever does a wrong or wrongs himself but then seeks forgiveness of Allah will find Allah Forgiving and Merciful.

^{— Quran 4:110}

والذين إذا فعلوا فاحشة أو ظلموا أنفسهم ذكروا الله فاستغفروا لذنوبهم ومن يغفر الذنوب إلا الله ولم يصروا على ما فعلوا وهم يعلمون أولئك جزاؤهم مغفرة من ربهم وجنات تجري من تحتها الأنهار خالدين فيها ونعم أجر العاملين

And those who, when they commit an immorality or wrong themselves [by transgression], remember Allah and seek forgiveness for their sins - and who can forgive sins except Allah? - and [who] do not persist in what they have done while they know.

Those - their reward is forgiveness from their Lord and gardens beneath which rivers flow [in Paradise], wherein they will abide eternally; and excellent is the reward of the [righteous] workers.

^{— Quran 3:135}

In these verses Allah promised to forgive every sin after repentance, and every sin (by definition) also includes X. Note that this also includes Kufr and Shirk as Allah has stated that He will forgive these sins on repentance, see Quran 9:5 and Quran 25:70 etc. And when Kufr and Shirk can be forgiven so can every other sin since it is less than that.

Forgiveness in the absence of (sincere) repentance

If the person happens to die without repenting then he\she is deserving of punishment. However if X does not constitutes Shirk and Kufr, then there is still hope that Allah might forgive him\her if he\she is a believer at the time of death.

إن الله لا يغفر أن يشرك به ويغفر ما دون ذلك لمن يشاء

Indeed, Allah does not forgive association with Him, but He forgives what is less than that for whom He wills.

^{— Quran 4:48 also see Quran 47:34}

How to repent?

The process of repentance is covered in a dedicated question: Does the process of repentance differ significantly based on the sin? In short one must stop comitting in the sin, have sincere regret and remorse, seek forgiveness verbally, and resolve to not repeat the sin ever again. In some sins one is also required to pay Kaffarah. And in sins that are done against the people one should secure their forgiveness or compensate them. If one commits Kufr they also need to repeat the Shahadah.