I never used to like blowjobs before but now I do, is this normal?

No worries. There is nothing abnormal about your likes or dislikes changing. The fact that you now enjoy oral sex is neither good nor bad per se - but i suspect that it's good because you and your partner are enjoying it! oral sex is a fun part of our sex repertoire!
May be normal. It is normal for a person's likes and dislikes to change over time. A young person might enjoy bungee jumping every weekend, but 10 years later, the same person might prefer going on a bicycle journey with a spouse. Changes in sexual activity preferences are fine as long as the changes are rooted in a caring emotional bond with the partner, and not due to any abnormal personal psychological needs.