Only in very narrow circumstances.
If an employer can show that there is a particular need for someone of a certain age to do a job, this will count as a genuine occupational requirement (GOR) and will not be regarded as unlawful. However, in practice, few recruitment decisions are likely to benefit from this exemption, because of the danger that the employer is making stereotypical assumptions about you because of your age, instead of thinking about your individual aptitudes and skills.
Any GOR should be spelled out clearly in the job profile and/or person specification when you apply for the job.
An employer can refuse to offer you the job if you cannot comply with a statutory requirement. For example, it is not unlawful to refuse to employ a young worker who is not yet old enough to qualify for the driving licence for the vehicle they need to drive.