It's no contradiction when you understand that "aionion times" had a beginning, which is implied by the fact that there was a "before" these "aionion times". As Titus 1:2 says:
before eternal times (ACVI Greek-English Interlinear)
before the ages of time (IGNT Greek-English Interlinear)
before times eternal (Apostolic Greek Polygot, Greek-English Interlinear)
Study Bible - Online Greek Hebrew KJV Parallel Interlinear Tools
before times eonian (Online Greek-English Interlinear)
http://www.scripture4all.org/OnlineInterlinear/NTpdf/tit1.pdf
before time eternal (Greek-English Interlinear)
Titus 1:2 Interlinear: upon hope of life age-during, which God, who doth not lie, did promise before times of ages,
Therefore, since aionion/eonian has a beginning in the Scriptures, it can never be eternal in the past. So if you define Christ Himself as aionion life, you are defining Him as having had a beginning. This denies the Trinity and the Deity of Christ. And contradicts your (and my) belief that Christ is God & always was God, just as the Father and the Holy Spirit.
The deceptive KJV obscures the fact of God's Word [and the Holy Spirit's] teaching that there was "before times aionion" & therefore "times aionion" are not eternal in the past. It follows from that that what is aionion cannot be eternal in the past.
Titus 1:2
KJV In hope of eternal life, which God, that cannot lie, promised before the world began;
Aside from the mistranslation "eternal" in some of the following versions, they translate the phrase in question - προ χρονων αιωνιων (pro chronon aionion) [before times eonian] - more accurately than KJV:
Berean Literal Bible
in the hope of eternal life, which God, who cannot lie, promised before time eternal
Jubilee Bible 2000
for the hope of eternal life, which God, who cannot lie, promised before the times of the ages
American Standard Version
in hope of eternal life, which God, who cannot lie, promised before times eternal;
Darby Bible Translation
in [the] hope of eternal life, which God, who cannot lie, promised before the ages of time,
English Revised Version
in hope of eternal life, which God, who cannot lie, promised before times eternal;
Weymouth New Testament
in hope of the Life of the Ages which God, who is never false to His word, promised before the commencement of the Ages.
Young's Literal Translation
upon hope of life age-during, which God, who doth not lie, did promise before times of ages,
AMP based on the hope and divine guarantee of eternal life, [the life] which God, who is ever truthful and without deceit, promised before the ages of time began,
DLNT on-the-basis-of the hope of eternal life which the non-lying God promised before eternal times—
EHV based on the hope of eternal life, which God, who cannot lie, promised before time began.
ESV in hope of eternal life, which God, who never lies, promised before the ages began
ESVUK in hope of eternal life, which God, who never lies, promised before the ages began
EXB That faith and that knowledge ·come from [or lead to] the ·hope for [confidence/certainty of] ·life forever [eternal life], which God, who never lies, promised to us before ·time began [L eternal times].
JUB for the hope of eternal life, which God, who cannot lie, promised before the times of the ages
LEB in the hope of eternal life which God, who does not lie, promised before eternal ages,
MOUNCE for the sake of the hope of eternal life, which God, who does not lie, promised before times eternal,
NRSV in the hope of eternal life that God, who never lies, promised before the ages began—
NRSVA in the hope of eternal life that God, who never lies, promised before the ages began—
NRSVACE in the hope of eternal life that God, who never lies, promised before the ages began—
NRSVCE in the hope of eternal life that God, who never lies, promised before the ages began—
NTE in the hope of the life of the coming age. God, who never lies, promised this before the ages began,
OJB The mekor (basis) of this is a tikvah of Chayyei Olam which Hashem Who cannot speak sheker [BAMIDBAR 24:19; SHMUEL ALEF 15:29] promised before the Yamim HaOlam (days of eternity),
in expectation of life eonian, which God, Who does not lie, promises before times eonian (CLV)
In hope of life age-abiding; which God, who cannot lie, promised before age-during times, (Ro)
in hope of life age-lasting, which promised the not false God before times age-lasting, (Diag)
on hope of eternal life which the God who does not lie promised before the eternal times (GLT)
before eternal times (ACVI Greek-English Interlinear)
before the ages of time (IGNT Greek-English Interlinear)
before times eternal (Apostolic Greek Polygot, Greek-English Interlinear)
Study Bible - Online Greek Hebrew KJV Parallel Interlinear Tools
before times eonian (Online Greek-English Interlinear)
http://www.scripture4all.org/OnlineInterlinear/NTpdf/tit1.pdf
before time eternal (Greek-English Interlinear)
Titus 1:2 Interlinear: upon hope of life age-during, which God, who doth not lie, did promise before times of ages,
Eternity in the Bible by Gerry Beauchemin – Hope Beyond Hell