is htacces limit access to wp-admin to my ip only enough for wordpress security
restricting access to wp-admin from one IP is part of a good security plan. Making regular backups of your site, long passwords, plugins like wordfence are others. you should read about Hardening WordPress.
Even using htacess to restrict access to wp-admin will not stop the attacks. There are million and millions of zombie computers running scripts attempting to login to sites not to mention the search engins trying to grab your information.
One thing I do to a couple of my sites is ban entire ranges of IP addresses (I suport a local church’s website in the US, no need for anyone using an IP from China, russia, Peru, Nigeria, Germany etc to access the site) – I’m currently banning over 65,000,000 IP addresses and adding more every week aor so. i go thru my logs and check out where the IP is coming from (if you want to lookup the IP google ‘ip lookup)